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SEMINAR OF CHEMISTRY FOR YEAR 2012-2013


             Hydrogen
    for XI std chemistry
• FROM



         &
HYDROGEN
INTRODUCTION

 Hydrogen, chemical element that exists as a gas at
  room temperature. When hydrogen gas burns in air, it
  forms water. French chemist Antoine Lavoisier named
  hydrogen from the Greek words for ―water former.‖
 Hydrogen has the smallest atoms of any element. A
  hydrogen atom contains one proton, and only one
  electron . The proton is the center, or nucleus, of the
  hydrogen atom, and the electron travels around the
  nucleus.
 Pure hydrogen exists as hydrogen gas, in which pairs
  of hydrogen atoms bond together to make molecules.
HOW WAS HYDRGOEN FOUND

 Discovered by Henry Cavendish
 Hydrogen was discovered in London
 It was discovered in the year of 1766
The hydrogen atom
consisting the proton
in the centre or the
nucleus of the hydro-
gen atom and the ele-
ctron travelling aroun-
d the nucleus.
The Hydrogen H2 Molecule
POSITION IN THE PERIODIC TABLE


 Hydrogen is the first element in the periodic table of
  the elements and is represented by the symbol H.
 Hydrogen, with only one proton, is the simplest
  element. It is usually placed in Period 1 and Group 1
  of the periodic table.
 Hydrogen can combine chemically with almost every
  other element and forms more compounds than does
  any other element. These compounds include water,
  minerals, and hydrocarbons—compounds made of
  hydrogen and carbon—such as petroleum and natural
  gas.
Position of hydrogen in the periodic table
How is Hydrogen Produced?

 Reforming fossil fuels
   Heat hydrocarbons with steam
   Produce H2 and CO
 Electrolysis of water
   Use electricity to split water into O2 and H2
 High Temperature Electrolysis
   Experimental
 Biological processes
   Very common in nature
   Experimental in laboratories
STEAM REFORMING
 From any hydrocarbon
   Natural gas typically used
 Water (steam) and hydrocarbon mixed at high
  temperature (700–1100 °C)
   Steam (H2O) reacts with methane (CH4)
   CH4 + H2O → CO + 3 H2 - 191.7 kJ/mol
 The thermodynamic efficiency comparable to (or
  worse than) an internal combustion engine
   Difficult to motivate investment in technology
CARBON MONOXIDE REFORMING


 Additional hydrogen can be recovered using
  carbon monoxide (CO)
   low-temp (130°C) water gas shift reaction
   CO + H2O → CO2 + H2 + 40.4 kJ/mol
 Oxygen (O) atom stripped from steam
   Oxidizes the carbon (C)
   Liberates hydrogen bound to C and O2
Hydrogen Steam Reforming
Hydrogen Steam Reforming Plants
Electrolysis of Water (H2O)
Renewable Energy for Electrolysis




                     http://www.howstuffworks.com/hydrogen-economy4.htm
Biomass Electrolysis Module
High Temperature Electrolysis
 Electrolysis at high temperatures
 Use less energy to split water
Biological H2 Creation
                         Nature has very simple
                         methods to split water

                         Scientists are working to
                         mimic these processes in
                         the lab; then commercially
PHYSICAL PROPERTIES OF H2
 Dihydrogen is a :
 Colourless ,
 Odourless
 Tasteless
 Combustible gas
 Lighter than air
 Insoluble in water
 It‘s melting point – 18.73 K
    & boiling point – 23.67 K
CHEMICAL PROPERTIES OF H2

 Hydrogen gas does not usually react with other chemicals
  at room temperature, because the bond between the
  hydrogen atoms is very strong and can only be broken
  with a large amount of energy.
 Since its orbital is incomplete with 1s1 electronic
  configuration, it does combine with almost all the elements
  .
  It accomplishes reactions by:
  1.loss of one e- to give H+
  2.gain of an e- to form H-
  3.sharing electrons to form a single covalent bond.
Bosch reaction
Hydrogenation
Dehydrogenation
Transfer hydrogenation
Hydrogenolysis
BOSCH REACTION
        The Bosch reaction is a chemical reaction between carbon
dioxide and hydrogen that produces elemental carbon (graphite), water and
a 10% return of invested heat. This reaction requires the introduction of
iron as a catalyst and requires a temperature level of 530-730 degrees
Celsius.
The overall reaction is as follows:

       CO2(g) + 2 H2(g) → C(s) + 2 H2O(g)
        The above reaction is actually the result of two reactions. The first
reaction, the reverse water gas shift reaction, is a fast one.
        CO2 + H2 → CO + H2O
The second reaction controls the reaction rate.
        CO + H2 → C + H2O
The overall reaction produces 2.3×103 joules for every gram of
carbon produced at 650 °C. Reaction temperatures are in the range
of 450 to 600 °C.
The reaction can be accelerated in the presence of
an iron, cobalt or nickel catalyst. Ruthenium also serves to speed
up the reaction.
        Together with the Sabatier reaction the Bosch reaction is
studied as a way to remove carbon dioxide and to generate clean
water aboard a space station
        The reaction is also used to produce graphite
for radiocarbon dating with Accelerator Mass Spectrometry.
        It is named after the German chemist Carl Bosch.
Hydrogenation

        To treat with hydrogen - is a chemical reaction between
molecular hydrogen (H2) and another compound or element, usually in
the presence of a catalyst. The process is commonly employed
to reduce or saturate organic compounds. Hydrogenation typically
constitutes the addition of pairs of hydrogen atoms to a molecule,
generally an alkene. Catalysts are required for the reaction to be usable;
non-catalytic hydrogenation takes place only at very high
temperatures. Hydrogen adds to double and triple bonds in hydrocarbons
        Because of the importance of hydrogen, many related reactions
have been developed for its use. Most hydrogenations use gaseous
hydrogen (H2), but some involve the alternative sources of hydrogen, not
H2: these processes are called transfer hydrogenations. The reverse
reaction, removal of hydrogen from a molecule, is called dehydrogenation.
A reaction where bonds are broken while hydrogen is added is
called hydrogenolysis, a reaction that may occur to carbon-carbon and
carbon-heteroatom (oxygen, nitrogen or halogen) bonds. Hydrogenation
differs from protonation or hydride addition: in hydrogenation, the
products have the same charge as the reactants.
        An illustrative example of a hydrogenation reaction is the
addition of hydrogen to maleic acid to form succinic acid. Numerous
important applications of this petrochemical are found in pharmaceutical
and food industries. Hydrogenation of unsaturated
fats produces saturated fats and, in some cases, trans fats.
DEHYDROGENATION
        Dehydrogenation is a chemical reaction that involves the
removal of hydrogen from a molecule as (H2). It is the reverse process
of hydrogenation. Dehydrogenation reactions may be either large scale
industrial processes or smaller scale laboratory procedures.

   Classes of the reaction
 There are a variety of classes of dehydrogenations:
 •Aromatization — Six-membered alicyclic rings can be aromatized
 in the presence of hydrogenation catalysts, the elements sulfur
 and selenium, or quinones (such as DDQ).
 •Oxidation — The conversion
 of alcohols to ketones or aldehydes can be effected by metal catalysts
 such as copper chromite. In the Oppenauer oxidation, hydrogen is
 transferred from one alcohol to another to bring about the oxidation.
• Dehydrogenation of amines — amines can be converted
to nitriles using a variety of reagents, such as Iodine
pentafluoride (IF5).
• Dehydrogenation of paraffin's and olefins — paraffin's like n-
pentane and isopentane can be converted
to pentene and isoprene using chromium (III) oxide as a catalyst at
500 degree C.

        Dehydrogenation converts saturated fats to unsaturated fats.
Enzymes that catalyze dehydrogenation are called dehydrogenases.
Dehydrogenation processes are used extensively to produce styrene in
the fine chemicals, oleochemicals, petrochemicals, and detergents
industries.
TRANSFER HYDROGENATION
Is the addition of hydrogen (H2; dihydrogen
in inorganic and organometallic chemistry) to a molecule from a source other
than gaseous H2. It is applied in industry and in organic synthesis, in part
because of the inconvenience and expense of using gaseous H2. One large scale
application of transfer hydrogenation is coal liquefaction using "donor solvents"
such as tetralin
                        HYDROGENOLYSIS
 Hydrogenolysis is a chemical reaction whereby a carbon–carbon or
 carbon–heteroatom single bond is cleaved or undergoes "lysis" by
 hydrogen. The heteroatom may vary, but it usually is oxygen, nitrogen, or
 sulfur. A related reaction is hydrogenation, where hydrogen is added to the
 molecule, without cleaving bonds. Usually hydrogenolysis is conducted
 catalytically using hydrogen gas.
HYDROGEN STORAGE OPTIONS

       PHYSICAL STORAGE                       CHEMICAL STORAGE
            Molecular                             Dissociative
               H2                                  H2    2H


             REVERSIBLE               REVERSIBLE          NON-REVERSIBLE

                                                REFORMED FUEL

                                               HYDROLYZED FUEL      DECOMPOSED
                                                                       FUEL
COMPRESSED      HYBRID     LIQUID
   GAS          TANKS     HYDROGEN




                              CONVENTIONAL     COMPLEX METAL     LIGHT ELEMENT
                             METAL HYDRIDES      HYDRIDES          SYSTEMS
Compressed Storage

 Prototype vehicle tanks developed
 Efficient high-volume manufacturing
  processes needed
 Less expensive materials desired
    carbon fiber
    binder
 Evaluation of engineering factors
  related to safety required
   understanding of failure
     processes
Liquid Storage
 Prototype vehicle tanks developed
 Reduced mass and especially volume needed
 Reduced cost and development of high-volume production processes
  needed

   • Extend dormancy (time to start
     of ―boil off‖ loss) without
     increasing cost, mass, volume
   • Improve energy efficiency of
     liquefaction
Hybrid Physical Storage

 Compressed H2 @ cryogenic temperatures
   H2 density increases at lower temperatures
   further density increase possible through use of
    adsorbents – opportunity for new materials
 The best of both worlds, or the worst ??
 Concepts under development
Non-reversible On-board Storage

 On-board reforming of fuels has been rejected as a source of
  hydrogen because of packaging and cost
    energy station reforming to provide compressed hydrogen is still a
     viable option
 Hydrolysis hydrides suffer from high heat rejection on-board
  and large energy requirements for recycle
 On-board decomposition of specialty fuels is a real option
   need desirable recycle process
   engineering for minimum cost and ease of use
Reversible On-board Storage

 Reversible, solid state, on-board storage is the ultimate goal for
  automotive applications
 Accurate, fast computational techniques needed to scan new
  formulations and new classes of hydrides
 Thermodynamics of hydride systems can be “tuned” to improve
  system performance
   storage capacity
   temperature of hydrogen release
   kinetics/speed of hydrogen refueling
 Catalysts and additives may also improve storage
  characteristics
Hydrogen has three naturally
occurring isotopes,
denoted 1H, 2H and 3H. Other,
highly unstable nuclei (4H to 7H)
have been synthesized in the
laboratory but not observed in
nature
1H


1H  is the most common hydrogen isotope with
an abundance of more than 99.98%. Because
the nucleus of this isotope consists of only a
single proton, it is given the descriptive but
rarely used formal name protium.
2H

2H,  the other stable hydrogen isotope, is known as deuterium and
contains one proton and one neutron in its nucleus. Essentially all
deuterium in the universe is thought to have been produced at the
time of the Big Bang, and has endured since that time. Deuterium
is not radioactive, and does not represent a significant toxicity
hazard. Water enriched in molecules that include deuterium
instead of normal hydrogen is called heavy water. Deuterium and
its compounds are used as a non-radioactive label in chemical
experiments and in solvents for 1H-NMR spectroscopy. Heavy
water is used as a neutron moderator and coolant for nuclear
reactors. Deuterium is also a potential fuel for
commercial nuclear fusion
3H

3H   is known as tritium and contains one proton and two
neutrons in its nucleus. It is radioactive, decaying into helium-
3 through beta decay with a half-life of 12.32 years. It is so
radioactive that it can be used in luminous paint, making it
useful in such things as watches. The glass prevents the small
amount of radiation from getting out. Small amounts of
tritium occur naturally because of the interaction of cosmic
rays with atmospheric gases; tritium has also been released
during nuclear weapons tests. It is used in nuclear fusion
reactions, as a tracer in isotope geochemistry, and specialized
in self-powered lighting devices. Tritium has also been used in
chemical and biological labeling experiments as a radiolabe
4H

4H   contains one proton and three neutrons in its nucleus. It
is a highly unstable isotope of hydrogen. It has been
synthesized in the laboratory by bombarding tritium with
fast-moving deuterium nuclei. In this experiment, the
tritium nuclei captured neutrons from the fast-moving
deuterium nucleus. The presence of the hydrogen-4 was
deduced by detecting the emitted protons. Its atomic
mass is 4.02781 ± 0.00011. It decays through neutron
emission with a half-life of (1.39 ± 0.10) × 10−22 seconds.
5H


5H  is a highly unstable isotope of hydrogen. The
nucleus consists of a proton and four neutrons.
It has been synthesized in the laboratory by
bombarding tritium with fast-moving tritium
nuclei. In this experiment, one tritium nucleus
captures two neutrons from the other, becoming
a nucleus with one proton and four neutrons.
The remaining proton may be detected, and the
existence of hydrogen-5 deduced. It decays
through double neutron emission and has a half-
life of at least 9.1 × 10−22 seconds.
6H




6H decays through triple neutron
emission and has a half-life of
2.90×10−22 seconds. It consists of 1
proton and 5 neutrons.
7H


7H  consists of a proton and six neutrons. It was first
synthesized in 2003 by a group of Russian, Japanese
and French scientists at RIKEN's RI Beam Science
Laboratory by bombarding hydrogen with helium-
8 atoms. In the resulting reaction, the helium-8's
neutrons were donated to the hydrogen's nucleus.
The two remaining protons were detected by the
"RIKEN telescope", a device composed of several
layers of sensors, positioned behind the target of the
RI Beam cyclotron.
IMPORTANT

        Hydrogen is the only element that has different names
for its isotopes in common use today. During the early study of
radioactivity, various heavy radioactive isotopes were given
their own names, but such names are no longer used, except for
deuterium and tritium. The symbols D and T (instead
of2H and 3H) are sometimes used for deuterium and tritium,
but the corresponding symbol for protium, P, is already in use
for phosphorus and thus is not available for protium. In
its nomenclatural guidelines, the International Union of Pure
and Applied Chemistry allows any of D, T, 2H, and 3H to be
used, although 2H and 3H are preferred.
Table:- Atomic And Physical Properties Of Isotopes Hydrogen

Property              Hydrogen              Deuterium              Tritium
Active (%)            99.985                0.0156                   -15
Abundance                                                          10
Relative at mass      1.008                 2.014                  3.016
Melting point         13.96                 18.73                  20.62
Boiling point         20.39                 23.67                  25.0
Density               0.09                  0.18                   0.27
E of fusion           0.117                 0.197                    _
E of vaporization     0.904                 0.197                    _
E of dissociation     435.88                443.35                   _
Interneuclar dist     74.14                 74.14                    _
Electronic gain e     -73                    _                       _
Covalent radius       37                     _                       _
Ionic radius          208                    _                       _
USES OF HYDROGEN
 ENERGY SECURITY



 ECONOMIC PROSPERITY




 ENVIRONMENTAL STEWARDSHIP
INTERIOR OF THE SUN

                The Sun‘s energy is
                 produced in the core
                 through nuclear fusion
                 of hydrogen atoms into
                 helium. Gases in the
                 core are about 150
                 times as dense as water
                 and reach temperatures
                 as high as 16 million
                 degrees C (29 million
                 degrees F).
Presence of hydrogen in volcanoes and
          in our food particles
Cont….

 Hydrogen accounts for about 73 percent of the
  observed mass of the universe and is the most
  common element in the universe.
 Hydrogen atoms were the first atoms to form in
  the early universe and that the atoms of the other
  elements formed later from the hydrogen atoms.
 About 90 percent of the atoms in the universe are
  hydrogen, about 9 percent are helium, and all the
  other elements account for less than 1 percent.
Cont….

          Common Molecules:
          Many common molecules
          contain hydrogen. In these
          molecules, butane
          contains ten hydrogen
          atoms, ammonia contains
          three hydrogen atoms, and
          water contains two
          hydrogen atoms.
Biomass                                                   Transportation
  Hydro
                                         HIGH EFFICIENCY
  Wind                                    & RELIABILITY           .
  Solar
Geothermal

 Nuclear
             With Carbon Sequestration




    Oil                                                      Distributed
                                         ZERO/NEAR ZERO      Generation
                                            EMISSIONS
  Coal

  Natural
   Gas
With advancement of science and technology we realize in order
to make our lives comfortable fossil fuels are depleating at an
alarming rate and will be exhausted soon. The electricity cannot
be stored to run automobiles. It is not possible to store and
transport nuclear energy. Hydrogen is another alternative
source of energy and hence called as ‘hydrogen economy’.
Hydrogen has some advantages as fuel
   • Available in abundance in combined form as water.
   • On combustion produces H2O. Hence pollution free.
   • H2-O2 fuel cell give more power.
   • Excellent reducing agent. Therefore can be used as
     substitute of carbon in reduction for processes in industry.
Flexibility Of Use

Transportation
  Desired range can be achieved with on-board hydrogen storage (unlike
    Battery Electric Vehicle)
  Can be used in internal combustion engines
  Trains, automobiles, buses, and ships
Buildings
  Combined heat, power, and fuel
  Reliable energy services for critical applications
  Grid independence
Industrial Sector
  Already plays an important role as a chemical
  Opportunities for additional revenue streams
Storing & Transporting Hydrogen

 Store and Transport as a Gas
   Bulky gas
   Compressing H2 requires energy
   Compressed H2 has far less energy than the same volume of
      gasoline
 Store and Transport as a Solid
     Sodium Borohydride
     Calcium Hydride
     Lithium Hydride
     Sodium Hydride
Transporting Hydrogen
Hydrogen-Powered Autos
Hydrogen-Powered Autos
Hydrogen-Powered Trucks
Hydrogen-Powered Aircraft




 Hydrogen powered passenger aircraft with cryogenic tanks along spine of
 fuselage. Hydrogen fuel requires about 4 times the volume of standard jet
 fuel (kerosene).
Hydrogen-Powered Rockets
Guts of a Fuel Cell Vehicle
Fuel Cell Life

While fuel cells do wear
out over time, A PEM
fuel cell in a vehicle
should have a 4,000
hour service life, while
stationary applications
should last 40,000
hours.
Hydrogen Safety
 Hydrogen     Gasoline

            Three Second
              seconds

                           Fuel leak simulation
                             Hydrogen on left
                             Gasoline on right
                             Equivalent energy release

             One minute
Advantages of a Hydrogen Economy

 Waste product of burning H2 is water
 Elimination of fossil fuel pollution
 Elimination of greenhouse gases
 Elimination of economic dependence
 Distributed production
 The stuff of stars
Disadvantages of Hydrogen Economy

 Low energy densities
 Difficulty in handling, storage, transport
 Requires an entirely new infrastructure
 Creates CO2 if made from fossil fuels
 Low net energy yields
   Much energy needed to create hydrogen
 Possible environmental problems
   Ozone depletion (not proven at this point)
"I believe that water will one day be employed as fuel, that
hydrogen and oxygen which constitute it, used singly or
together, will furnish an inexhaustible source of heat and
light, of an intensity of which coal is not capable. I believe
then that when the deposits of coal are exhausted, we shall
heat and warm ourselves with water. Water will be the coal
of the future."

                       Jules Vernes (1870) L´île mystérieuse
RISKS OF
HYDROGEN
HYDROGEN DAMAGE
        Hydrogen damage is the generic name given to a large number
of metal degradation processes due to interaction with hydrogen.
Hydrogen is present practically everywhere, several kilometers above the
earth and inside the earth. Engineering materials are exposed to hydrogen and
they may interact with it resulting in various kinds of structural damage.
Damaging effects of hydrogen in metallic materials have been known since
1875 when W. H. Johnson reported ―some remarkable changes produced
in iron by the action of hydrogen and acids‖. During the intervening years
many similar effects have been observed in different structural materials,
such as steel, aluminum, titanium, and zirconium. Because of the
technological importance of hydrogen damage, many people explored the
nature, causes and control measures of hydrogen related degradation of
metals. Hardening, embrittlement and internal damage are the main hydrogen
damage processes in metals. This article consists of a classification of
hydrogen damage, brief description of the various processes and their
mechanisms, and some guidelines for the control of hydrogen damage.
HYDROGEN EMBRITTLEMENT


  Hydrogen embrittlement is the process by which various
   metals, most importantly high-strength steel,
   become brittle and fracture following exposure
   to hydrogen. Hydrogen embrittlement is often the result of
   unintentional introduction of hydrogen into susceptible
   metals during forming or finishing operations and
   increases cracking in the material.
  Hydrogen embrittlement is also used to describe the
   formation of zircaloy hydride. Use of the term in this
   context is common in the nuclear industry.
HYDROGEN LEAK TESTING
        Hydrogen leak testing is the normal way in which
a hydrogen pressure vessel or installation is checked for leaks or flaws. There
are various tests.
        The Hydrostatic test, The vessel is filled with a nearly incompressible
liquid - usually water or oil - and examined for leaks or permanent changes in
shape. The test pressure is always considerably more than the operating
pressure to give a margin for safety, typically 150% of the operating pressure.
        The Burst test, The vessel is filled with a gas and tested for leaks. The
test pressure is always considerably more than the operating pressure to give
a margin for safety, typically 200% or more of the operating pressure.
The Helium leak test, The leak detection method uses helium (the lightest
inert gas) as a tracer gas and detects it in concentrations as small as one part
in 10 million. The helium is selected primarily because it penetrates small
leaks readily.
Usually a vacuum inside the object is created with an external
pump connected to the instrument.
Alternatively helium can be injected inside the product while the
product itself is enclosed in a vacuum chamber connected to the
instrument. In this case Burst and leakage tests can be combined in
one operation.
       The Hydrogen sensor, The object is filled with a mixture of
5% hydrogen/ 95% nitrogen, (below 5.7% hydrogen is non-
flammable (ISO-10156). This is called typically a sniffing test.
       The handprobe connected to the microelectronic hydrogen
sensors is used to check the object. An audio signal increases in
proximity of a leak. Detection of leaks go down to 5x10-7 cubic
centimeters per second. Compared to the helium test: hydrogen is
cheaper than helium, no need for a vacuum, the instrument could be
cheaper.
HYDROGEN SAFETY



          Hydrogen safety covers the safe production,
 handling and use of hydrogen. Hydrogen poses unique
 challenges due to its ease of leaking, low-energy ignition,
 wide range of combustible fuel-air mixtures, buoyancy, and
 its ability to embrittle metals that must be accounted for to
 ensure safe operation. Liquid hydrogen poses additional
 challenges due to its increased density and the extremely
 low temperatures needed to keep it in liquid form.
OCCURRENCE OF DIHYDROGEN
 Hydrogen is the tenth most common element on Earth.
  Because it is so light, though, hydrogen accounts for
  less than 1 percent of Earth's total mass. It is usually
  found in compounds. Pure hydrogen gas rarely occurs
  in nature, although volcanoes and some oil wells
  release small amounts of hydrogen gas.
 Hydrogen is in nearly every compound in the human
  body. For example, it is in keratin, the main protein
  that forms our hair and skin, and in the enzymes that
  digest food in our intestines. Hydrogen is in the
  molecules in food that provide energy: fats, proteins,
  and carbohydrates.
PREPARATION OF DIHYDROGEN

 Laboratory preparation of dihydrogen:
 1.It is usually prepared by the reaction of granulated
 zinc with dilute hydrochloric acid. The chemical
 equation for this reaction is the following:
           Zn + 2HCl → ZnCl2 + H2

 2.It can also be prepared by the reaction of zinc with
 aqueous alkali. The chemical equation for this
 reaction is the following:
          Zn +2NaOH            Na2ZnO2 + H2
                           (Sodium zincate)
Dihydrogen in 3D
Cont….

 Commercial production of dihydrogen:
1. Electrolysis of acidified water using platinum
   electrodes gives hydrogen.
   2 H2O electrolysis 2H2 + O2
   This chemical equation shows that two water
   molecules (with electricity), form two molecules of
   hydrogen gas and one molecule of oxygen gas.
2.High purity (>99.95%) dihydrogen is obtained by
   electrolysing warm aqueous barium hydroxide
   solution between nickel electrodes.
Commercial production of dihydrogen
Cont….
3. It is obtained as a byproduct in the manufacture of sodium
   hydroxide & chlorine by the electrolysis of brine solutions
   .
   The reactions that takes place are:
   At anode : 2Cl-          Cl2 +2e-
   At cathode: 2H2O + 2e-         H2 + 2OH-
    The overall reaction is
               2Na+ + 2Cl- +2H2O


           Cl2 + H2 + 2Na+ + 2OH-
Cont….
4. Reaction of steam on hydrocarbons at high temperature in
   the presence of catalyst yields hydrogen. e.g.,
   CH4 + H2O 1270K   Ni
                            CO + 3H2

 The mixture of CO & H2 is called water gas.
 It is used for synthesis of methanol & a number of
  hydrocarbons, therefore it is called synthesis gas or
  ‘syngas’.
 The production of dihydrogen can be increased by reacting
  carbon monoxide with steam in the presence iron chromate
  as catalyst.
  CO + H2O 673K CO2 + H2
               Catalyst


 This is called water-gas shift reaction. Carbon dioxide is
  removed by scrubbing with sodium arsenite solution.
CHEMISTRY OF DIHYDROGEN
 Reaction with halogens:
  It reacts with halogens, X2 to give hydrogen halides,
  HX,
           H2+X2          2HX (X= F, Cl, Br, I)
   While the reaction with fluorine occurs even in the
   dark, with iodine it requires a catalyst.
 Reaction with dioxygen:
  It reacts with dioxygen to form water. The reaction is
   highly exothermic.
      2H2 + O2 catalyst or heating 2H2O ; H = -285.9 kJ
   mol-1
Cont….
 Reaction with dinitrogen:
  With dintrogen it forms ammonia.
        3H2 +N2 673K,200atm 2NH3; H=-92.6 kJ mol-1
  This is the method for the manufacture of ammonia by Haber
  process.
  Haber Process:
  German chemist and Nobel laureate Fritz Haber developed an
  economical method of producing ammonia from air and
  seawater. In his process, nitrogen is separated from the other
  components of air through distillization. Hydrogen is obtained
  from seawater by passing an electric current through the water.
  The nitrogen and hydrogen are combined to form ammonia
  (NH3).
Cont….
 Reaction with metals:
  Hydrogen also forms ionic bonds with some metals, at
  a high temperature, creating a compound called a
  hydride.
         H2 +2M           2MH
  Where M is an alkali metal (e.g. lithium, sodium,
  potassium, rubidium, cesium, and francium.)
 Reactions with metal ions & metal oxides:
  It reduces some metal ions in aqueous solution &
  oxides of metals (less active than iron ) into
  corresponding metals.
        H2+Pd 2+         Pd + 2H+
       yH2 +MxOy        xM + yH2O
Cont….
 Reactions with organic compounds:
  1.Hydrogenation of vegetable oils using nickel as
  catalyst gives edible fats. (margarine & vanaspati
  ghee).

 2.Hydroformylation of olefins yields aldehydes which
 further undergo reduction to give alcohols.

       H2+CO+RCH=CH2             RCH2CH2CHO

    H2 +RCH2CH2CHO             RCH2CH2CH2OH
USES OF DIHYDROGEN
 The largest use of dihydrogen is in the synthesis of
  ammonia which is used in the manufacture of nitric
    acid & nitrogenous fertilizers.
   Dihydrogen is used in the manufacture of vanaspati
    fat.
   It is used in the manufacture of bulk organic
    chemicals, particularly methanol.
           CO + 2H2 catalyst cobalt CH3OH
   It is widely used for the manufacture of metal
    hydrides.
   It is used for the preparation of hydrogen chloride, a
    highly useful chemical.
Cont……


 In metallurgical processes, it is widely used to
  reduce heavy metal oxides to metals.
 Atomic hydrogen & oxy-hydrogen torches find use
  for cutting & welding purposes.
 It is used as a rocket fuel in space research.
 Dihydrogen is used in the fuel cells for generating
  electrical energy. It has many advantages over the
  conventional fossil fuels & electric power.
DIHYDROGEN AS A FUEL:

  Dihydrogen releases large quantities of heat on
     combustion.
    Dihydrogen can release more energy than petrol's.
    HYDROGEN ECONOMY: The basic principle of
     hydrogen economy is the transportation & storage of
     energy in the form of liquid or gaseous dihydrogen.
    Energy is transmitted in the form of dihydrogen & not
     as electric power.
    It is also use in fuel cell for generation of electric
     power.
Various uses of dihydrogen
HYDRIDES
 Dihydrogen also forms ionic bonds with some metals,
  at a high temperature, creating a compound called a
  hydride.

 If E is the symbol of an element then hydride can be
  expressed as EHX (e.g. MgH2) or EmHn (e.g. B2H6).

 The hydrides are classified into three categories:
  1.Ionic or saline or saltlike hydrides.
  2.Covalent or molecular hydrides.
  3.Metallic or non-stoichiometric hydrides.
Nearly all elements are able to form hydride
                compound
IONIC OR SALINE HYDRIDES
 These are stoichiometric compounds of dihydrogen
  formed with most of the s-block elements which are
  highly electropositive in character.
 Covalent character is found in the lighter metal hydrides
  (e.g. LiH, BeH2 & MgH2).
 The ionic hydrides are crystalline, non-volatile & non-
  conducting in solid state.
 Their melts conduct electricity & on electrolysis liberate
  dihydrogen gas at anode, which confirms the existence of
  H-ion.
             2H-(melt) anode H2+2e-
 Saline hydrides react violently with water producing
  dihydrogen gas .
              NaH + H2O          NaOH + H2
COVALENT OR MOLECULAR HYDRIDE
 Dihydrogen forms molecular compounds with most of
  the p-block elements. For e.g. CH4, NH3, H2O & HF.
 Hydrogen compounds of non metals have also been
  considered as hydrides. Being covalent they are volatile
  compounds.
 Molecular hydrides are further classified according to the
  relative number of electrons & bonds in their Lewis
  structure into:
  1.Electron-deficient
  2.Electron-precise
  3.Electron-rich hydrides.
ELECTRON-               ELECTRON-PRECISE       ELECTRON-RICH
DEFICIENT               HYDRIDES               HYDRIDES
HYDRIDES
Has few electrons for   Have the required      Have excess electrons
Lewis structure.        number of electrons    which are present as
                        for Lewis structure.   lone pair.

Elements of group 13    Elements of group 14 Electrons of group 15-
forms these             forms these          17 forms such
compounds.              compounds.           compounds.

For e.g. Diborane       For e.g. CH4.          For e.g.NH3-
(B2H6).                                        has1lonepair, H2O-
                                               has 2 lone pairs.
They act as Lewis                              They act as Lewis
acids i.e. electron                            bases i.e. electron
acceptor.                                      donor.
METALLIC HYDRIDES
 These are formed by many d-block & f-block elements.
 The metals of group 7,8 & 9 do not form hydride.
 These hydrides conduct heat & electricity though not as
    efficiently as their parent metals do.
   Unlike saline hydrides, they are almost non-stoichiometric,
    being deficient in hydrogen. For e.g. LaH2.87 & YbH2.55.
   Law of constant composition does not hold good.
   The property of absorption of hydrogen on transition metal
    is widely used in catalytic reduction/hydrogenation
    reactions for the preparation of large number of
    compounds.
    Some of the metals can accommodate a very large volume
    of hydrogen & can be used as its storage media.
Water

 A major part of all living organisms is made up of
  water.

 Human body has about 65% & some plants have as
  much as 95% water.

 It is a crucial compound for the survival of all life
  forms.

 It is a solvent of great importance.
Different uses of water
Physical properties of water

 It is a colourless & tasteless liquid.
 The unusual properties of water in the condensed
  phase (liquid & solid) are due to the presence of
  extensive hydrogen bonding between water molecules.
 Water has a higher specific heat, thermal conductivity,
  surface tension, dipole moment & dielectric constant
  when compared to other liquids.
 It is an excellent solvent for transportation of ions &
  molecules required for plant & animal metabolism.
 Due to hydrogen bonding with polar molecules, even
  covalent compounds like alcohol & carbohydrates
  dissolve in water.
STRUCTURE OF WATER

 In the gas phase water is a bent molecule with a bond angle of
  104.50 ,

  and O-H bond length of 95.7 pm.

 It is a highly polar molecule .



 In the liquid phase water molecules are associated together by
  hydrogen bonds.

 Density of water is more than that of ice.
Hydrogen Bonding in Water:


Hydrogen bonds are chemical bonds that form between
molecules containing a hydrogen atom bonded to a strongly
electronegative atom . Because the electronegative atom
pulls the electron from the hydrogen atom, the atoms form
a very polar molecule, meaning one end is negatively
charged and the other end is positively charged. Hydrogen
bonds form between these molecules because the negative
ends of the molecules are attracted to the positive ends of
other molecules, and vice versa. Hydrogen bonding makes
water form a liquid at room temperature.
STRUCTURE OF ICE:


 Ice has a highly ordered three dimensional
  hydrogen bonded structure.
 Examination of ice crystals with x-rays shows that
  each oxygen atom is surrounded tetrahedrally by
  four other oxygen atoms a distance of 276pm.
 Hydrogen bonding gives ice a rather open type
  structure with wide holes. These holes can hold
  some other molecules of appropriate size
  interstitially.
Structure of ice
Chemical properties of water
 Amphoteric nature: it has the ability to act as an acid as
  well as a base i.e., it behaves as an amphoteric substance.
  In the Bronsted sense it acts an acid with NH3 and a base
  with H2S.
      H2O+ NH3           OH- + NH4+

      H2O+ H2S           H3O++ HS-

   The auto-protolysis (self- ionization) of water takes place as
  follows:
      H2O +H2O          H3O+ +OH-
      acid-1   base-2   acid-2   base-1
REDOX REACTIONS INVOLVING WATER
 Water can be easily reduced to dihydrogen by highly
  electropositive metals.
                  2H2O +2Na           2NaOH +H2
   Thus ,it is a great source of dihydrogen.

 Water is oxidised to O2 during photosynthesis.
       6CO2 +12H2O              C6H12O6 + 6H2O +6O2

 With fluorine also it is oxidised toO2.
          2F2 + 2H2O            4H+ + 4F- +O2
Hydrolysis reaction
 Due to high dielectric constant, it has a very strong
  hydrating tendency. It dissolves many ionic
  compounds. However, certain covalent& some
  ionic compounds are hydrolysed in water.
   P4O10 +6H2O          4H3PO4

   SiCl4 +2H2O           SiO2 + 4HCl

   N3- + 3H2O            NH3 +3OH-
A hydrolysis process generally involves water
HYDRATES FORMATION
 From aqueous solutions many salts can be crystallised
 as hydrated salts. Such an association of water is of
 different types viz.,
 (i) coordinated water e.g.,
       [Cr(H2O)6 ]3+ 3Cl-
 (ii) interstitial water e.g.,
        BaCl2.2H2O
 (iii) hydrogen-bonded water e.g.,
         [Cu(H2O)4]2+SO42-.H2O in CuSO4.5H2O
HYDROGEN
 PEROXIDE
HYDROGEN PEROXIDE:
 Hydrogen peroxide is an important chemical used in pollution
  control treatment of domestic & industrial effluents.
  PREPARATION:
 It can be prepared by the following methods:
  1.Acidifying barium peroxide & removing excess water by
  evaporation under reduced pressure gives hydrogen peroxide.
    BaO2.8H2O+H2SO4              BaSO4+H2O2+8H2O
 2.Preoxodisulphate, obtained by electrolytic oxidation of
 acidified sulphate solutions at high current density, on
 hydrolysis yields hydrogen peroxide.
  2HSO4- electrolysis HO3SOOSO3H hydrolysis 2HSO4-
 +2H++H2O2
Cont….
  This method is now used for the laboratory preparation of D2O2.

          K2S2O8+2D2O          2KDSO4+D2O2

 3.Industially it is prepared by the auto-oxidation of 2-
    alklylanthraquinols.

    2-ethylanthraquinol           H2O2+(oxidised product)

  In this case 1% H2O2 is formed. It is extracted with water &
   concentrated to 30% (by mass) by distillation under reduced
   pressure. It can be further concentrated to 85% by careful
   distillation under low pressure. The remaining water can be
   frozen out to obtain pure H2O2.
Preparation of hydrogen peroxide
PHYSICAL PROPERTIES:
 The pure state H2O2 is an almost
    colourless liquid
   Meting point - 272.4K.
   Boiling point - 423K
   Vapour pressure (298K) – 1.9mmHg.
   H2O2 is miscible with water in all proportions &
    forms a hydrate H2O2.H2O.
   A 30% solution of H2O2 is marketed as ‗100V‘
    hydrogen peroxide. It means that 1ml of 30% H2O2
    solution will give 100V of oxygen at STP.
   Hydrogen peroxide has a non-planar structure.
CHEMICAL PROPERTIES:
 It acts as an oxidising as well as reducing     agent
  in both acidic & alkaline media.
  1.Oxidising action in acidic medium:
      2Fe2+ +2H+ +H2O2        2Fe3+ +2H2O

            PbS +4H2O2            PbSO4+4H2O

   2.Reducing action in acidic medium:
    2MnO4- +6H+ +5H2O2         2Mn2+ +8H2O+5O2

             HOCl +H2O2           H3O+ +Cl- +O2
Cont….
3.Oxidising action in basic medium:
   2Fe2+ +H2O2       2Fe3+ +2OH-

  Mn2+ +H2O2        Mn4+ +2OH-

4.Reducing action in basic medium:
   I2+H2O2+2OH-       2I-+2H2O+O2

2MnO4-+3H2O2         2MnO2+3O2+2H2O+2OH-
STORAGE

 H2O2 decomposes slowly on exposure to light.
              2H2O2        2H2O+O2
 In the presence of metal surfaces or traces of
  alkali, the above reaction is catalysed. It is,
  therefore stored in wax-lined glass or plastic
  vessels in dark.
 It is kept away from dust because dust can induce
  explosive decomposition of the compound.
USES:

 It is used as hair bleach & as a mild disinfectant. As an
    antiseptic it is sold in the market as perhydrol.
   It is used to manufacture chemicals like sodium
    perborate & per-carbonate, which are used in high
    quality detergents.
   It is used in the synthesis of hydroquinone, tartaric
    acid & certain food products & pharmaceuticals etc.
   It is employed in the industries as bleaching agent for
    textiles, paper pulp, leather, oils, fats etc.
   It is also used in environmental chemistry.
HEAVY WATER,D2O
 It is extensively used as a moderator in nuclear reactors
    & in exchange reactions for the study of reaction
    mechanisms.
   It can be prepared by exhaustive electrolysis of water or
    as a by-product in some fertilizer industries.
   PHYSICAL PROPERTIES:
   Molecular mass: 20.0276 g/mol.
   Melting point: 276.8K.
   Boiling point: 374.4K.
Cont…..

 The bottom ice cubes were made with heavy
  water, which is water that uses deuterium
  hydrogen (nucleus with an extra neutron) not
  regular hydrogen which has no neutron.
Production of Hard water
USES:
 It is used for the preparation of other deuterium
  compounds. For e.g.
  CaC2 + 2D2O       C2D2 + Ca(OD)2
  SO3 + D2O         D2SO4
  Al4C3 + 12D2O       3CD4 + 4Al(OD)3
PROJECT HYDROGEN SUMMARY:-
1)Hydrogen is the most abundant and simplest element
in the universe.
2)Hydrogen has no elasticity.
3)Hydrogen is flameable.
4)Hydrogen is energy carrier.
5)Hydrogen can be cooled and stored as a liquid.
6)Atomic hydrogen is highly reactive.
7)Nascent hydrogen is very reactive form of hydrogen.
 Liquid and compressed hydrogen storage
   Technically feasible; in use on prototype vehicles
   Focus is on meeting packaging, mass, and cost targets
   Both methods fall below energy density goals
   Unique vehicle architecture and design could enable efficient
    packaging and extended range
 Solid state storage
   Fundamental discovery and intense development necessary
    “Idea-rich” research environment
PROJECT HELPERS
  GUIDANCE :- HEENA SHAIKH MADAM

  10TH , 11TH TEXTBOOKS.
  HYDROGEN REFERENCE BOOK (BRITISH
   LIBIRARY).
  INTERNET :- GOOGLE,YAHOO ETC.
  INTERNET :- MAPS , STATITICS , PHOTOS
   ETC.
ALL ABOUT OF HYDROGEN IN A PRESENTATION

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ALL ABOUT OF HYDROGEN IN A PRESENTATION

  • 1. SEMINAR OF CHEMISTRY FOR YEAR 2012-2013 Hydrogen for XI std chemistry • FROM &
  • 3. INTRODUCTION  Hydrogen, chemical element that exists as a gas at room temperature. When hydrogen gas burns in air, it forms water. French chemist Antoine Lavoisier named hydrogen from the Greek words for ―water former.‖  Hydrogen has the smallest atoms of any element. A hydrogen atom contains one proton, and only one electron . The proton is the center, or nucleus, of the hydrogen atom, and the electron travels around the nucleus.  Pure hydrogen exists as hydrogen gas, in which pairs of hydrogen atoms bond together to make molecules.
  • 4. HOW WAS HYDRGOEN FOUND  Discovered by Henry Cavendish  Hydrogen was discovered in London  It was discovered in the year of 1766
  • 5. The hydrogen atom consisting the proton in the centre or the nucleus of the hydro- gen atom and the ele- ctron travelling aroun- d the nucleus.
  • 6. The Hydrogen H2 Molecule
  • 7. POSITION IN THE PERIODIC TABLE  Hydrogen is the first element in the periodic table of the elements and is represented by the symbol H.  Hydrogen, with only one proton, is the simplest element. It is usually placed in Period 1 and Group 1 of the periodic table.  Hydrogen can combine chemically with almost every other element and forms more compounds than does any other element. These compounds include water, minerals, and hydrocarbons—compounds made of hydrogen and carbon—such as petroleum and natural gas.
  • 8. Position of hydrogen in the periodic table
  • 9.
  • 10. How is Hydrogen Produced?  Reforming fossil fuels  Heat hydrocarbons with steam  Produce H2 and CO  Electrolysis of water  Use electricity to split water into O2 and H2  High Temperature Electrolysis  Experimental  Biological processes  Very common in nature  Experimental in laboratories
  • 11. STEAM REFORMING  From any hydrocarbon  Natural gas typically used  Water (steam) and hydrocarbon mixed at high temperature (700–1100 °C)  Steam (H2O) reacts with methane (CH4)  CH4 + H2O → CO + 3 H2 - 191.7 kJ/mol  The thermodynamic efficiency comparable to (or worse than) an internal combustion engine  Difficult to motivate investment in technology
  • 12. CARBON MONOXIDE REFORMING  Additional hydrogen can be recovered using carbon monoxide (CO)  low-temp (130°C) water gas shift reaction  CO + H2O → CO2 + H2 + 40.4 kJ/mol  Oxygen (O) atom stripped from steam  Oxidizes the carbon (C)  Liberates hydrogen bound to C and O2
  • 16. Renewable Energy for Electrolysis http://www.howstuffworks.com/hydrogen-economy4.htm
  • 18. High Temperature Electrolysis  Electrolysis at high temperatures  Use less energy to split water
  • 19. Biological H2 Creation Nature has very simple methods to split water Scientists are working to mimic these processes in the lab; then commercially
  • 20.
  • 21.
  • 22.
  • 23. PHYSICAL PROPERTIES OF H2  Dihydrogen is a :  Colourless ,  Odourless  Tasteless  Combustible gas  Lighter than air  Insoluble in water  It‘s melting point – 18.73 K & boiling point – 23.67 K
  • 24. CHEMICAL PROPERTIES OF H2  Hydrogen gas does not usually react with other chemicals at room temperature, because the bond between the hydrogen atoms is very strong and can only be broken with a large amount of energy.  Since its orbital is incomplete with 1s1 electronic configuration, it does combine with almost all the elements . It accomplishes reactions by: 1.loss of one e- to give H+ 2.gain of an e- to form H- 3.sharing electrons to form a single covalent bond.
  • 26. BOSCH REACTION The Bosch reaction is a chemical reaction between carbon dioxide and hydrogen that produces elemental carbon (graphite), water and a 10% return of invested heat. This reaction requires the introduction of iron as a catalyst and requires a temperature level of 530-730 degrees Celsius. The overall reaction is as follows: CO2(g) + 2 H2(g) → C(s) + 2 H2O(g) The above reaction is actually the result of two reactions. The first reaction, the reverse water gas shift reaction, is a fast one. CO2 + H2 → CO + H2O The second reaction controls the reaction rate. CO + H2 → C + H2O
  • 27. The overall reaction produces 2.3×103 joules for every gram of carbon produced at 650 °C. Reaction temperatures are in the range of 450 to 600 °C. The reaction can be accelerated in the presence of an iron, cobalt or nickel catalyst. Ruthenium also serves to speed up the reaction. Together with the Sabatier reaction the Bosch reaction is studied as a way to remove carbon dioxide and to generate clean water aboard a space station The reaction is also used to produce graphite for radiocarbon dating with Accelerator Mass Spectrometry. It is named after the German chemist Carl Bosch.
  • 28. Hydrogenation To treat with hydrogen - is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically constitutes the addition of pairs of hydrogen atoms to a molecule, generally an alkene. Catalysts are required for the reaction to be usable; non-catalytic hydrogenation takes place only at very high temperatures. Hydrogen adds to double and triple bonds in hydrocarbons Because of the importance of hydrogen, many related reactions have been developed for its use. Most hydrogenations use gaseous hydrogen (H2), but some involve the alternative sources of hydrogen, not H2: these processes are called transfer hydrogenations. The reverse reaction, removal of hydrogen from a molecule, is called dehydrogenation.
  • 29. A reaction where bonds are broken while hydrogen is added is called hydrogenolysis, a reaction that may occur to carbon-carbon and carbon-heteroatom (oxygen, nitrogen or halogen) bonds. Hydrogenation differs from protonation or hydride addition: in hydrogenation, the products have the same charge as the reactants. An illustrative example of a hydrogenation reaction is the addition of hydrogen to maleic acid to form succinic acid. Numerous important applications of this petrochemical are found in pharmaceutical and food industries. Hydrogenation of unsaturated fats produces saturated fats and, in some cases, trans fats.
  • 30. DEHYDROGENATION Dehydrogenation is a chemical reaction that involves the removal of hydrogen from a molecule as (H2). It is the reverse process of hydrogenation. Dehydrogenation reactions may be either large scale industrial processes or smaller scale laboratory procedures. Classes of the reaction There are a variety of classes of dehydrogenations: •Aromatization — Six-membered alicyclic rings can be aromatized in the presence of hydrogenation catalysts, the elements sulfur and selenium, or quinones (such as DDQ). •Oxidation — The conversion of alcohols to ketones or aldehydes can be effected by metal catalysts such as copper chromite. In the Oppenauer oxidation, hydrogen is transferred from one alcohol to another to bring about the oxidation.
  • 31. • Dehydrogenation of amines — amines can be converted to nitriles using a variety of reagents, such as Iodine pentafluoride (IF5). • Dehydrogenation of paraffin's and olefins — paraffin's like n- pentane and isopentane can be converted to pentene and isoprene using chromium (III) oxide as a catalyst at 500 degree C. Dehydrogenation converts saturated fats to unsaturated fats. Enzymes that catalyze dehydrogenation are called dehydrogenases. Dehydrogenation processes are used extensively to produce styrene in the fine chemicals, oleochemicals, petrochemicals, and detergents industries.
  • 32.
  • 33. TRANSFER HYDROGENATION Is the addition of hydrogen (H2; dihydrogen in inorganic and organometallic chemistry) to a molecule from a source other than gaseous H2. It is applied in industry and in organic synthesis, in part because of the inconvenience and expense of using gaseous H2. One large scale application of transfer hydrogenation is coal liquefaction using "donor solvents" such as tetralin HYDROGENOLYSIS Hydrogenolysis is a chemical reaction whereby a carbon–carbon or carbon–heteroatom single bond is cleaved or undergoes "lysis" by hydrogen. The heteroatom may vary, but it usually is oxygen, nitrogen, or sulfur. A related reaction is hydrogenation, where hydrogen is added to the molecule, without cleaving bonds. Usually hydrogenolysis is conducted catalytically using hydrogen gas.
  • 34.
  • 35. HYDROGEN STORAGE OPTIONS PHYSICAL STORAGE CHEMICAL STORAGE Molecular Dissociative H2 H2 2H REVERSIBLE REVERSIBLE NON-REVERSIBLE REFORMED FUEL HYDROLYZED FUEL DECOMPOSED FUEL COMPRESSED HYBRID LIQUID GAS TANKS HYDROGEN CONVENTIONAL COMPLEX METAL LIGHT ELEMENT METAL HYDRIDES HYDRIDES SYSTEMS
  • 36. Compressed Storage  Prototype vehicle tanks developed  Efficient high-volume manufacturing processes needed  Less expensive materials desired  carbon fiber  binder  Evaluation of engineering factors related to safety required  understanding of failure processes
  • 37. Liquid Storage  Prototype vehicle tanks developed  Reduced mass and especially volume needed  Reduced cost and development of high-volume production processes needed • Extend dormancy (time to start of ―boil off‖ loss) without increasing cost, mass, volume • Improve energy efficiency of liquefaction
  • 38. Hybrid Physical Storage  Compressed H2 @ cryogenic temperatures  H2 density increases at lower temperatures  further density increase possible through use of adsorbents – opportunity for new materials  The best of both worlds, or the worst ??  Concepts under development
  • 39. Non-reversible On-board Storage  On-board reforming of fuels has been rejected as a source of hydrogen because of packaging and cost  energy station reforming to provide compressed hydrogen is still a viable option  Hydrolysis hydrides suffer from high heat rejection on-board and large energy requirements for recycle  On-board decomposition of specialty fuels is a real option  need desirable recycle process  engineering for minimum cost and ease of use
  • 40. Reversible On-board Storage  Reversible, solid state, on-board storage is the ultimate goal for automotive applications  Accurate, fast computational techniques needed to scan new formulations and new classes of hydrides  Thermodynamics of hydride systems can be “tuned” to improve system performance  storage capacity  temperature of hydrogen release  kinetics/speed of hydrogen refueling  Catalysts and additives may also improve storage characteristics
  • 41. Hydrogen has three naturally occurring isotopes, denoted 1H, 2H and 3H. Other, highly unstable nuclei (4H to 7H) have been synthesized in the laboratory but not observed in nature
  • 42. 1H 1H is the most common hydrogen isotope with an abundance of more than 99.98%. Because the nucleus of this isotope consists of only a single proton, it is given the descriptive but rarely used formal name protium.
  • 43. 2H 2H, the other stable hydrogen isotope, is known as deuterium and contains one proton and one neutron in its nucleus. Essentially all deuterium in the universe is thought to have been produced at the time of the Big Bang, and has endured since that time. Deuterium is not radioactive, and does not represent a significant toxicity hazard. Water enriched in molecules that include deuterium instead of normal hydrogen is called heavy water. Deuterium and its compounds are used as a non-radioactive label in chemical experiments and in solvents for 1H-NMR spectroscopy. Heavy water is used as a neutron moderator and coolant for nuclear reactors. Deuterium is also a potential fuel for commercial nuclear fusion
  • 44. 3H 3H is known as tritium and contains one proton and two neutrons in its nucleus. It is radioactive, decaying into helium- 3 through beta decay with a half-life of 12.32 years. It is so radioactive that it can be used in luminous paint, making it useful in such things as watches. The glass prevents the small amount of radiation from getting out. Small amounts of tritium occur naturally because of the interaction of cosmic rays with atmospheric gases; tritium has also been released during nuclear weapons tests. It is used in nuclear fusion reactions, as a tracer in isotope geochemistry, and specialized in self-powered lighting devices. Tritium has also been used in chemical and biological labeling experiments as a radiolabe
  • 45. 4H 4H contains one proton and three neutrons in its nucleus. It is a highly unstable isotope of hydrogen. It has been synthesized in the laboratory by bombarding tritium with fast-moving deuterium nuclei. In this experiment, the tritium nuclei captured neutrons from the fast-moving deuterium nucleus. The presence of the hydrogen-4 was deduced by detecting the emitted protons. Its atomic mass is 4.02781 ± 0.00011. It decays through neutron emission with a half-life of (1.39 ± 0.10) × 10−22 seconds.
  • 46. 5H 5H is a highly unstable isotope of hydrogen. The nucleus consists of a proton and four neutrons. It has been synthesized in the laboratory by bombarding tritium with fast-moving tritium nuclei. In this experiment, one tritium nucleus captures two neutrons from the other, becoming a nucleus with one proton and four neutrons. The remaining proton may be detected, and the existence of hydrogen-5 deduced. It decays through double neutron emission and has a half- life of at least 9.1 × 10−22 seconds.
  • 47. 6H 6H decays through triple neutron emission and has a half-life of 2.90×10−22 seconds. It consists of 1 proton and 5 neutrons.
  • 48. 7H 7H consists of a proton and six neutrons. It was first synthesized in 2003 by a group of Russian, Japanese and French scientists at RIKEN's RI Beam Science Laboratory by bombarding hydrogen with helium- 8 atoms. In the resulting reaction, the helium-8's neutrons were donated to the hydrogen's nucleus. The two remaining protons were detected by the "RIKEN telescope", a device composed of several layers of sensors, positioned behind the target of the RI Beam cyclotron.
  • 49. IMPORTANT Hydrogen is the only element that has different names for its isotopes in common use today. During the early study of radioactivity, various heavy radioactive isotopes were given their own names, but such names are no longer used, except for deuterium and tritium. The symbols D and T (instead of2H and 3H) are sometimes used for deuterium and tritium, but the corresponding symbol for protium, P, is already in use for phosphorus and thus is not available for protium. In its nomenclatural guidelines, the International Union of Pure and Applied Chemistry allows any of D, T, 2H, and 3H to be used, although 2H and 3H are preferred.
  • 50. Table:- Atomic And Physical Properties Of Isotopes Hydrogen Property Hydrogen Deuterium Tritium Active (%) 99.985 0.0156 -15 Abundance 10 Relative at mass 1.008 2.014 3.016 Melting point 13.96 18.73 20.62 Boiling point 20.39 23.67 25.0 Density 0.09 0.18 0.27 E of fusion 0.117 0.197 _ E of vaporization 0.904 0.197 _ E of dissociation 435.88 443.35 _ Interneuclar dist 74.14 74.14 _ Electronic gain e -73 _ _ Covalent radius 37 _ _ Ionic radius 208 _ _
  • 51. USES OF HYDROGEN  ENERGY SECURITY  ECONOMIC PROSPERITY  ENVIRONMENTAL STEWARDSHIP
  • 52. INTERIOR OF THE SUN  The Sun‘s energy is produced in the core through nuclear fusion of hydrogen atoms into helium. Gases in the core are about 150 times as dense as water and reach temperatures as high as 16 million degrees C (29 million degrees F).
  • 53. Presence of hydrogen in volcanoes and in our food particles
  • 54. Cont….  Hydrogen accounts for about 73 percent of the observed mass of the universe and is the most common element in the universe.  Hydrogen atoms were the first atoms to form in the early universe and that the atoms of the other elements formed later from the hydrogen atoms.  About 90 percent of the atoms in the universe are hydrogen, about 9 percent are helium, and all the other elements account for less than 1 percent.
  • 55. Cont….  Common Molecules: Many common molecules contain hydrogen. In these molecules, butane contains ten hydrogen atoms, ammonia contains three hydrogen atoms, and water contains two hydrogen atoms.
  • 56. Biomass Transportation Hydro HIGH EFFICIENCY Wind & RELIABILITY . Solar Geothermal Nuclear With Carbon Sequestration Oil Distributed ZERO/NEAR ZERO Generation EMISSIONS Coal Natural Gas
  • 57. With advancement of science and technology we realize in order to make our lives comfortable fossil fuels are depleating at an alarming rate and will be exhausted soon. The electricity cannot be stored to run automobiles. It is not possible to store and transport nuclear energy. Hydrogen is another alternative source of energy and hence called as ‘hydrogen economy’. Hydrogen has some advantages as fuel • Available in abundance in combined form as water. • On combustion produces H2O. Hence pollution free. • H2-O2 fuel cell give more power. • Excellent reducing agent. Therefore can be used as substitute of carbon in reduction for processes in industry.
  • 58. Flexibility Of Use Transportation Desired range can be achieved with on-board hydrogen storage (unlike Battery Electric Vehicle) Can be used in internal combustion engines Trains, automobiles, buses, and ships Buildings Combined heat, power, and fuel Reliable energy services for critical applications Grid independence Industrial Sector Already plays an important role as a chemical Opportunities for additional revenue streams
  • 59. Storing & Transporting Hydrogen  Store and Transport as a Gas  Bulky gas  Compressing H2 requires energy  Compressed H2 has far less energy than the same volume of gasoline  Store and Transport as a Solid  Sodium Borohydride  Calcium Hydride  Lithium Hydride  Sodium Hydride
  • 64. Hydrogen-Powered Aircraft Hydrogen powered passenger aircraft with cryogenic tanks along spine of fuselage. Hydrogen fuel requires about 4 times the volume of standard jet fuel (kerosene).
  • 66. Guts of a Fuel Cell Vehicle
  • 67. Fuel Cell Life While fuel cells do wear out over time, A PEM fuel cell in a vehicle should have a 4,000 hour service life, while stationary applications should last 40,000 hours.
  • 68. Hydrogen Safety Hydrogen Gasoline Three Second seconds Fuel leak simulation Hydrogen on left Gasoline on right Equivalent energy release One minute
  • 69. Advantages of a Hydrogen Economy  Waste product of burning H2 is water  Elimination of fossil fuel pollution  Elimination of greenhouse gases  Elimination of economic dependence  Distributed production  The stuff of stars
  • 70. Disadvantages of Hydrogen Economy  Low energy densities  Difficulty in handling, storage, transport  Requires an entirely new infrastructure  Creates CO2 if made from fossil fuels  Low net energy yields  Much energy needed to create hydrogen  Possible environmental problems  Ozone depletion (not proven at this point)
  • 71. "I believe that water will one day be employed as fuel, that hydrogen and oxygen which constitute it, used singly or together, will furnish an inexhaustible source of heat and light, of an intensity of which coal is not capable. I believe then that when the deposits of coal are exhausted, we shall heat and warm ourselves with water. Water will be the coal of the future." Jules Vernes (1870) L´île mystérieuse
  • 73. HYDROGEN DAMAGE Hydrogen damage is the generic name given to a large number of metal degradation processes due to interaction with hydrogen. Hydrogen is present practically everywhere, several kilometers above the earth and inside the earth. Engineering materials are exposed to hydrogen and they may interact with it resulting in various kinds of structural damage. Damaging effects of hydrogen in metallic materials have been known since 1875 when W. H. Johnson reported ―some remarkable changes produced in iron by the action of hydrogen and acids‖. During the intervening years many similar effects have been observed in different structural materials, such as steel, aluminum, titanium, and zirconium. Because of the technological importance of hydrogen damage, many people explored the nature, causes and control measures of hydrogen related degradation of metals. Hardening, embrittlement and internal damage are the main hydrogen damage processes in metals. This article consists of a classification of hydrogen damage, brief description of the various processes and their mechanisms, and some guidelines for the control of hydrogen damage.
  • 74. HYDROGEN EMBRITTLEMENT  Hydrogen embrittlement is the process by which various metals, most importantly high-strength steel, become brittle and fracture following exposure to hydrogen. Hydrogen embrittlement is often the result of unintentional introduction of hydrogen into susceptible metals during forming or finishing operations and increases cracking in the material.  Hydrogen embrittlement is also used to describe the formation of zircaloy hydride. Use of the term in this context is common in the nuclear industry.
  • 75. HYDROGEN LEAK TESTING Hydrogen leak testing is the normal way in which a hydrogen pressure vessel or installation is checked for leaks or flaws. There are various tests. The Hydrostatic test, The vessel is filled with a nearly incompressible liquid - usually water or oil - and examined for leaks or permanent changes in shape. The test pressure is always considerably more than the operating pressure to give a margin for safety, typically 150% of the operating pressure. The Burst test, The vessel is filled with a gas and tested for leaks. The test pressure is always considerably more than the operating pressure to give a margin for safety, typically 200% or more of the operating pressure. The Helium leak test, The leak detection method uses helium (the lightest inert gas) as a tracer gas and detects it in concentrations as small as one part in 10 million. The helium is selected primarily because it penetrates small leaks readily.
  • 76. Usually a vacuum inside the object is created with an external pump connected to the instrument. Alternatively helium can be injected inside the product while the product itself is enclosed in a vacuum chamber connected to the instrument. In this case Burst and leakage tests can be combined in one operation. The Hydrogen sensor, The object is filled with a mixture of 5% hydrogen/ 95% nitrogen, (below 5.7% hydrogen is non- flammable (ISO-10156). This is called typically a sniffing test. The handprobe connected to the microelectronic hydrogen sensors is used to check the object. An audio signal increases in proximity of a leak. Detection of leaks go down to 5x10-7 cubic centimeters per second. Compared to the helium test: hydrogen is cheaper than helium, no need for a vacuum, the instrument could be cheaper.
  • 77. HYDROGEN SAFETY Hydrogen safety covers the safe production, handling and use of hydrogen. Hydrogen poses unique challenges due to its ease of leaking, low-energy ignition, wide range of combustible fuel-air mixtures, buoyancy, and its ability to embrittle metals that must be accounted for to ensure safe operation. Liquid hydrogen poses additional challenges due to its increased density and the extremely low temperatures needed to keep it in liquid form.
  • 78.
  • 79.
  • 80. OCCURRENCE OF DIHYDROGEN  Hydrogen is the tenth most common element on Earth. Because it is so light, though, hydrogen accounts for less than 1 percent of Earth's total mass. It is usually found in compounds. Pure hydrogen gas rarely occurs in nature, although volcanoes and some oil wells release small amounts of hydrogen gas.  Hydrogen is in nearly every compound in the human body. For example, it is in keratin, the main protein that forms our hair and skin, and in the enzymes that digest food in our intestines. Hydrogen is in the molecules in food that provide energy: fats, proteins, and carbohydrates.
  • 81. PREPARATION OF DIHYDROGEN  Laboratory preparation of dihydrogen: 1.It is usually prepared by the reaction of granulated zinc with dilute hydrochloric acid. The chemical equation for this reaction is the following: Zn + 2HCl → ZnCl2 + H2 2.It can also be prepared by the reaction of zinc with aqueous alkali. The chemical equation for this reaction is the following: Zn +2NaOH Na2ZnO2 + H2 (Sodium zincate)
  • 83. Cont….  Commercial production of dihydrogen: 1. Electrolysis of acidified water using platinum electrodes gives hydrogen. 2 H2O electrolysis 2H2 + O2 This chemical equation shows that two water molecules (with electricity), form two molecules of hydrogen gas and one molecule of oxygen gas. 2.High purity (>99.95%) dihydrogen is obtained by electrolysing warm aqueous barium hydroxide solution between nickel electrodes.
  • 85. Cont…. 3. It is obtained as a byproduct in the manufacture of sodium hydroxide & chlorine by the electrolysis of brine solutions . The reactions that takes place are: At anode : 2Cl- Cl2 +2e- At cathode: 2H2O + 2e- H2 + 2OH- The overall reaction is 2Na+ + 2Cl- +2H2O Cl2 + H2 + 2Na+ + 2OH-
  • 86. Cont…. 4. Reaction of steam on hydrocarbons at high temperature in the presence of catalyst yields hydrogen. e.g., CH4 + H2O 1270K Ni CO + 3H2  The mixture of CO & H2 is called water gas.  It is used for synthesis of methanol & a number of hydrocarbons, therefore it is called synthesis gas or ‘syngas’.  The production of dihydrogen can be increased by reacting carbon monoxide with steam in the presence iron chromate as catalyst. CO + H2O 673K CO2 + H2 Catalyst  This is called water-gas shift reaction. Carbon dioxide is removed by scrubbing with sodium arsenite solution.
  • 87. CHEMISTRY OF DIHYDROGEN  Reaction with halogens: It reacts with halogens, X2 to give hydrogen halides, HX, H2+X2 2HX (X= F, Cl, Br, I) While the reaction with fluorine occurs even in the dark, with iodine it requires a catalyst.  Reaction with dioxygen: It reacts with dioxygen to form water. The reaction is highly exothermic. 2H2 + O2 catalyst or heating 2H2O ; H = -285.9 kJ mol-1
  • 88. Cont….  Reaction with dinitrogen: With dintrogen it forms ammonia. 3H2 +N2 673K,200atm 2NH3; H=-92.6 kJ mol-1 This is the method for the manufacture of ammonia by Haber process. Haber Process: German chemist and Nobel laureate Fritz Haber developed an economical method of producing ammonia from air and seawater. In his process, nitrogen is separated from the other components of air through distillization. Hydrogen is obtained from seawater by passing an electric current through the water. The nitrogen and hydrogen are combined to form ammonia (NH3).
  • 89. Cont….  Reaction with metals: Hydrogen also forms ionic bonds with some metals, at a high temperature, creating a compound called a hydride. H2 +2M 2MH Where M is an alkali metal (e.g. lithium, sodium, potassium, rubidium, cesium, and francium.)  Reactions with metal ions & metal oxides: It reduces some metal ions in aqueous solution & oxides of metals (less active than iron ) into corresponding metals. H2+Pd 2+ Pd + 2H+ yH2 +MxOy xM + yH2O
  • 90. Cont….  Reactions with organic compounds: 1.Hydrogenation of vegetable oils using nickel as catalyst gives edible fats. (margarine & vanaspati ghee). 2.Hydroformylation of olefins yields aldehydes which further undergo reduction to give alcohols. H2+CO+RCH=CH2 RCH2CH2CHO H2 +RCH2CH2CHO RCH2CH2CH2OH
  • 91. USES OF DIHYDROGEN  The largest use of dihydrogen is in the synthesis of ammonia which is used in the manufacture of nitric acid & nitrogenous fertilizers.  Dihydrogen is used in the manufacture of vanaspati fat.  It is used in the manufacture of bulk organic chemicals, particularly methanol. CO + 2H2 catalyst cobalt CH3OH  It is widely used for the manufacture of metal hydrides.  It is used for the preparation of hydrogen chloride, a highly useful chemical.
  • 92. Cont……  In metallurgical processes, it is widely used to reduce heavy metal oxides to metals.  Atomic hydrogen & oxy-hydrogen torches find use for cutting & welding purposes.  It is used as a rocket fuel in space research.  Dihydrogen is used in the fuel cells for generating electrical energy. It has many advantages over the conventional fossil fuels & electric power.
  • 93. DIHYDROGEN AS A FUEL:  Dihydrogen releases large quantities of heat on combustion.  Dihydrogen can release more energy than petrol's.  HYDROGEN ECONOMY: The basic principle of hydrogen economy is the transportation & storage of energy in the form of liquid or gaseous dihydrogen.  Energy is transmitted in the form of dihydrogen & not as electric power.  It is also use in fuel cell for generation of electric power.
  • 94. Various uses of dihydrogen
  • 95.
  • 96.
  • 97.
  • 98. HYDRIDES  Dihydrogen also forms ionic bonds with some metals, at a high temperature, creating a compound called a hydride.  If E is the symbol of an element then hydride can be expressed as EHX (e.g. MgH2) or EmHn (e.g. B2H6).  The hydrides are classified into three categories: 1.Ionic or saline or saltlike hydrides. 2.Covalent or molecular hydrides. 3.Metallic or non-stoichiometric hydrides.
  • 99. Nearly all elements are able to form hydride compound
  • 100. IONIC OR SALINE HYDRIDES  These are stoichiometric compounds of dihydrogen formed with most of the s-block elements which are highly electropositive in character.  Covalent character is found in the lighter metal hydrides (e.g. LiH, BeH2 & MgH2).  The ionic hydrides are crystalline, non-volatile & non- conducting in solid state.  Their melts conduct electricity & on electrolysis liberate dihydrogen gas at anode, which confirms the existence of H-ion. 2H-(melt) anode H2+2e-  Saline hydrides react violently with water producing dihydrogen gas . NaH + H2O NaOH + H2
  • 101. COVALENT OR MOLECULAR HYDRIDE  Dihydrogen forms molecular compounds with most of the p-block elements. For e.g. CH4, NH3, H2O & HF.  Hydrogen compounds of non metals have also been considered as hydrides. Being covalent they are volatile compounds.  Molecular hydrides are further classified according to the relative number of electrons & bonds in their Lewis structure into: 1.Electron-deficient 2.Electron-precise 3.Electron-rich hydrides.
  • 102. ELECTRON- ELECTRON-PRECISE ELECTRON-RICH DEFICIENT HYDRIDES HYDRIDES HYDRIDES Has few electrons for Have the required Have excess electrons Lewis structure. number of electrons which are present as for Lewis structure. lone pair. Elements of group 13 Elements of group 14 Electrons of group 15- forms these forms these 17 forms such compounds. compounds. compounds. For e.g. Diborane For e.g. CH4. For e.g.NH3- (B2H6). has1lonepair, H2O- has 2 lone pairs. They act as Lewis They act as Lewis acids i.e. electron bases i.e. electron acceptor. donor.
  • 103. METALLIC HYDRIDES  These are formed by many d-block & f-block elements.  The metals of group 7,8 & 9 do not form hydride.  These hydrides conduct heat & electricity though not as efficiently as their parent metals do.  Unlike saline hydrides, they are almost non-stoichiometric, being deficient in hydrogen. For e.g. LaH2.87 & YbH2.55.  Law of constant composition does not hold good.  The property of absorption of hydrogen on transition metal is widely used in catalytic reduction/hydrogenation reactions for the preparation of large number of compounds.  Some of the metals can accommodate a very large volume of hydrogen & can be used as its storage media.
  • 104.
  • 105. Water  A major part of all living organisms is made up of water.  Human body has about 65% & some plants have as much as 95% water.  It is a crucial compound for the survival of all life forms.  It is a solvent of great importance.
  • 107.
  • 108. Physical properties of water  It is a colourless & tasteless liquid.  The unusual properties of water in the condensed phase (liquid & solid) are due to the presence of extensive hydrogen bonding between water molecules.  Water has a higher specific heat, thermal conductivity, surface tension, dipole moment & dielectric constant when compared to other liquids.  It is an excellent solvent for transportation of ions & molecules required for plant & animal metabolism.  Due to hydrogen bonding with polar molecules, even covalent compounds like alcohol & carbohydrates dissolve in water.
  • 109. STRUCTURE OF WATER  In the gas phase water is a bent molecule with a bond angle of 104.50 , and O-H bond length of 95.7 pm.  It is a highly polar molecule .  In the liquid phase water molecules are associated together by hydrogen bonds.  Density of water is more than that of ice.
  • 110. Hydrogen Bonding in Water: Hydrogen bonds are chemical bonds that form between molecules containing a hydrogen atom bonded to a strongly electronegative atom . Because the electronegative atom pulls the electron from the hydrogen atom, the atoms form a very polar molecule, meaning one end is negatively charged and the other end is positively charged. Hydrogen bonds form between these molecules because the negative ends of the molecules are attracted to the positive ends of other molecules, and vice versa. Hydrogen bonding makes water form a liquid at room temperature.
  • 111.
  • 112. STRUCTURE OF ICE:  Ice has a highly ordered three dimensional hydrogen bonded structure.  Examination of ice crystals with x-rays shows that each oxygen atom is surrounded tetrahedrally by four other oxygen atoms a distance of 276pm.  Hydrogen bonding gives ice a rather open type structure with wide holes. These holes can hold some other molecules of appropriate size interstitially.
  • 114. Chemical properties of water  Amphoteric nature: it has the ability to act as an acid as well as a base i.e., it behaves as an amphoteric substance. In the Bronsted sense it acts an acid with NH3 and a base with H2S. H2O+ NH3 OH- + NH4+ H2O+ H2S H3O++ HS- The auto-protolysis (self- ionization) of water takes place as follows: H2O +H2O H3O+ +OH- acid-1 base-2 acid-2 base-1
  • 115. REDOX REACTIONS INVOLVING WATER  Water can be easily reduced to dihydrogen by highly electropositive metals. 2H2O +2Na 2NaOH +H2 Thus ,it is a great source of dihydrogen.  Water is oxidised to O2 during photosynthesis. 6CO2 +12H2O C6H12O6 + 6H2O +6O2  With fluorine also it is oxidised toO2. 2F2 + 2H2O 4H+ + 4F- +O2
  • 116. Hydrolysis reaction  Due to high dielectric constant, it has a very strong hydrating tendency. It dissolves many ionic compounds. However, certain covalent& some ionic compounds are hydrolysed in water. P4O10 +6H2O 4H3PO4 SiCl4 +2H2O SiO2 + 4HCl N3- + 3H2O NH3 +3OH-
  • 117. A hydrolysis process generally involves water
  • 118. HYDRATES FORMATION  From aqueous solutions many salts can be crystallised as hydrated salts. Such an association of water is of different types viz., (i) coordinated water e.g., [Cr(H2O)6 ]3+ 3Cl- (ii) interstitial water e.g., BaCl2.2H2O (iii) hydrogen-bonded water e.g., [Cu(H2O)4]2+SO42-.H2O in CuSO4.5H2O
  • 119.
  • 121. HYDROGEN PEROXIDE:  Hydrogen peroxide is an important chemical used in pollution control treatment of domestic & industrial effluents. PREPARATION:  It can be prepared by the following methods: 1.Acidifying barium peroxide & removing excess water by evaporation under reduced pressure gives hydrogen peroxide. BaO2.8H2O+H2SO4 BaSO4+H2O2+8H2O 2.Preoxodisulphate, obtained by electrolytic oxidation of acidified sulphate solutions at high current density, on hydrolysis yields hydrogen peroxide. 2HSO4- electrolysis HO3SOOSO3H hydrolysis 2HSO4- +2H++H2O2
  • 122. Cont….  This method is now used for the laboratory preparation of D2O2. K2S2O8+2D2O 2KDSO4+D2O2 3.Industially it is prepared by the auto-oxidation of 2- alklylanthraquinols. 2-ethylanthraquinol H2O2+(oxidised product)  In this case 1% H2O2 is formed. It is extracted with water & concentrated to 30% (by mass) by distillation under reduced pressure. It can be further concentrated to 85% by careful distillation under low pressure. The remaining water can be frozen out to obtain pure H2O2.
  • 124. PHYSICAL PROPERTIES:  The pure state H2O2 is an almost colourless liquid  Meting point - 272.4K.  Boiling point - 423K  Vapour pressure (298K) – 1.9mmHg.  H2O2 is miscible with water in all proportions & forms a hydrate H2O2.H2O.  A 30% solution of H2O2 is marketed as ‗100V‘ hydrogen peroxide. It means that 1ml of 30% H2O2 solution will give 100V of oxygen at STP.  Hydrogen peroxide has a non-planar structure.
  • 125. CHEMICAL PROPERTIES:  It acts as an oxidising as well as reducing agent in both acidic & alkaline media. 1.Oxidising action in acidic medium: 2Fe2+ +2H+ +H2O2 2Fe3+ +2H2O PbS +4H2O2 PbSO4+4H2O 2.Reducing action in acidic medium: 2MnO4- +6H+ +5H2O2 2Mn2+ +8H2O+5O2 HOCl +H2O2 H3O+ +Cl- +O2
  • 126. Cont…. 3.Oxidising action in basic medium: 2Fe2+ +H2O2 2Fe3+ +2OH- Mn2+ +H2O2 Mn4+ +2OH- 4.Reducing action in basic medium: I2+H2O2+2OH- 2I-+2H2O+O2 2MnO4-+3H2O2 2MnO2+3O2+2H2O+2OH-
  • 127. STORAGE  H2O2 decomposes slowly on exposure to light. 2H2O2 2H2O+O2  In the presence of metal surfaces or traces of alkali, the above reaction is catalysed. It is, therefore stored in wax-lined glass or plastic vessels in dark.  It is kept away from dust because dust can induce explosive decomposition of the compound.
  • 128. USES:  It is used as hair bleach & as a mild disinfectant. As an antiseptic it is sold in the market as perhydrol.  It is used to manufacture chemicals like sodium perborate & per-carbonate, which are used in high quality detergents.  It is used in the synthesis of hydroquinone, tartaric acid & certain food products & pharmaceuticals etc.  It is employed in the industries as bleaching agent for textiles, paper pulp, leather, oils, fats etc.  It is also used in environmental chemistry.
  • 129.
  • 130.
  • 131. HEAVY WATER,D2O  It is extensively used as a moderator in nuclear reactors & in exchange reactions for the study of reaction mechanisms.  It can be prepared by exhaustive electrolysis of water or as a by-product in some fertilizer industries.  PHYSICAL PROPERTIES:  Molecular mass: 20.0276 g/mol.  Melting point: 276.8K.  Boiling point: 374.4K.
  • 132. Cont…..  The bottom ice cubes were made with heavy water, which is water that uses deuterium hydrogen (nucleus with an extra neutron) not regular hydrogen which has no neutron.
  • 134. USES:  It is used for the preparation of other deuterium compounds. For e.g. CaC2 + 2D2O C2D2 + Ca(OD)2 SO3 + D2O D2SO4 Al4C3 + 12D2O 3CD4 + 4Al(OD)3
  • 135.
  • 136. PROJECT HYDROGEN SUMMARY:- 1)Hydrogen is the most abundant and simplest element in the universe. 2)Hydrogen has no elasticity. 3)Hydrogen is flameable. 4)Hydrogen is energy carrier. 5)Hydrogen can be cooled and stored as a liquid. 6)Atomic hydrogen is highly reactive. 7)Nascent hydrogen is very reactive form of hydrogen.
  • 137.  Liquid and compressed hydrogen storage  Technically feasible; in use on prototype vehicles  Focus is on meeting packaging, mass, and cost targets  Both methods fall below energy density goals  Unique vehicle architecture and design could enable efficient packaging and extended range  Solid state storage  Fundamental discovery and intense development necessary “Idea-rich” research environment
  • 138. PROJECT HELPERS GUIDANCE :- HEENA SHAIKH MADAM  10TH , 11TH TEXTBOOKS.  HYDROGEN REFERENCE BOOK (BRITISH LIBIRARY).  INTERNET :- GOOGLE,YAHOO ETC.  INTERNET :- MAPS , STATITICS , PHOTOS ETC.