CHEMISTRY PROJECT ON AMOUNT OF TANNIC ACID PRESENT IN VARIOUS TEA SAMPLES

1. YEAR

2. INDEX
 CERTIFICATE
 ACKNOWLEDGEMENT
 INTRODUCTION
 AIM
 APPARATUS
 THEORY
 FORMULA USED
 PROCEDURE
 CALCULATIONS
 OBSERVATION TABLE
 INFERENCE
 BIBLIOGRAPHY

3. CERTIFICATE
Itisherebycertifiedthatoriginalandgenuineresearchwork
Iscarriedouttoinvestigateaboutthesubjectmatter
andtheRelateddatacollection hasbeen
completelysolelyandsatisfiedby
STUDENT’SNAME
regardingtheprojecttitled
AMOUNTOFTANNICACIDPRESENTINTEALEAVES
Signature of Chemistry teacher

4. ACKNOWLEDGEMENT
Iowemythankstoourprincipalforproviding
labouratoryfacilitiesandforhervaluableguidance.
Alotofthankstomychemistryteacher
TEACHER’SNAME
whoencouragedmeindoingthisprojectsuccessfully
andprovidedtherequiredapparatus
toperformmyprojectwork.
Student’sName
Note–Allthemistakescommittedinprojectaremyown

5. INTRODUCTION
Tea is made from the young leaves and buds
of the tea plant. Besides caffeine, tea leaves also
contain tannic acid .The relative amounts
of these substances are different in different
varieties of tea leaves, which is why, their
tastes and flavours are different.

6. Tannic acid is a specific commercial form of tannin,
a type of polyphenol. Its weak acidity (pKa around 10) is
due to the numerous phenol groups in the structure.
The chemical formula for commercial tannic acid is often
given as C76H52O46 having Molar mass 1,701.19 g/ mol
Solubility in Water: 2.85 g/cm³
The tea sample containing highest percentage of tannic
acid gives better flavour.

7. In fact it is a mixture of polygalloyl glucoses or polygalloyl
quinic acid esters with the number of galloyl moieties per
molecule ranging from 2 up to 12 depending on the plant
source used to extract the tannic acid. Commercial tannic
acid is usually extracted from any of the following plant
part:
Tara pods (Caesalpinia spinosa)
Gallnuts (Rhus semialata)
Sicilian Sumac leaves (Rhus coriaria).
Quercus infectoria

8. IUPAC name
2,3-dihydroxy-5-({[(2R,3R,4S,5R,6R)-3,4,5,6-tetrakis({3,4-dihydroxy-5-[(3,4,5-
trihydroxyphenyl)carbonyloxy]phenyl}carbonyloxy)oxan-2-yl]methoxy}carbonyl)
phenyl 3,4,5-trihydroxybenzoate
names
OTHER names
Acidum tannicum
Gallotannic acid
Digallic acid
Gallotannin
Tannimum
Querci-tannic acid
Querco-tannic acid

9. AIM
To compare the tannic acid content in the
various samples of tea leaves.

10. APPARATUS
Distilled Water, Bunsen burner, tripod stand, wire gauge,
beaker, funnel, China dish, filterpaper, 5gm of 3 different
tea leaves and Chemical Balance.
Chemicals Used:
Calcium Carbonate (CaCO 𝟑).
Sulphuric Acid (H2SO4)

11. THEORY
The tannic acid present on the tea leaves is precipitated
as calcium tannate by treatment of aqueous solution of
tea with Calcium Carbonate. Calcium tannate is then
hydrolysed with conc. H2SO4 and recrystallized from
water.

12. FORMULA USED
% OF TANNIC ACID PRESENT IN TEA LEAVES IS GIVEN BY
THE FOLLOWING FORMULA
=
weight of tannic acid present in tea leaves (y grams)
weight of tea leaves taken (x grams)
×100

13.  Weigh exactly 5gm of 1st sample of tea leaves.
 Take 100ml of distilled water in a beaker.
 Put tea leaves in above beaker and boil it for 10 minutes.
 Filter above boiled solution using funnel and filter paper.
 In filtrate add 2 grams of CaCO3 and boil it.
PROCEDURE

14.  Filter above boiled solution using funnel and filter
paper in another beaker. There will be a ppt. of Calcium
tannate on the filter paper.
 Keep filter paper aside and let it dry.
 Weigh the ppt. of tannic acid.
 Repeat the above steps for the other two samples.

15. CALCULATIONS
RED LABEL TEA (5 grams)
Amount of Tannic Acid = 0.620 grams
% of Tannic Acid = 0.620
5
×100 = 12.4 %
TATA TEA (5 grams)
Amount of Tannic Acid = 0.745 grams
% of Tannic Acid = 0.745
5
×100 = 14.9 %
LIPTON GREEN TEA (5 grams)
Amount of Tannic Acid = 0.130 grams
% of Tannic Acid = 0.130
5
×100 = 2.65 %

16. Observation table
BRAND NAME WEIGH OF TEA LEAVES
TAKEN
(x grams)
WEIGH OF TANNIC ACID
(y grams)
% OF TANIC ACID IN TEA
RED LABEL TEA 5 0.620 12.4
TATA TEA 5 0.745 14.9
LIPTON GREEN TEA 5 0.130 2.65

17. inference
12.4
14.9
2.6
0
2
4
6
8
10
12
14
16
% OF TANNIC ACID IN VARIOUS TEAS
RED LABEL TATA LIPTON GREEN TEA
The tea sample containing
highest percentage of tannic
acid gives better flavour.
Hence Tata tea considered
to be a better flavored tea.

18. BIBLIOGRAPHY
 Help of Chemistry Teacher
 Reference of Internet
 Chemistry Lab Manual
Student’s Name