Chem IP on Oxalate Ion in Guava.

1. Academic Year
2018-2019
Utkarsh Kushwaha
Roll No. 51
Chemistry Investigatory
Project
A Study of oxalate ion in guava

2. Acknowledgement
In the accomplishment of this project
successfully, many people have helped
me to carry out this investigatory project.
Most importantly, I thank God for giving
me knowledge to be able to understand
this topic and carry out this experiment.
I would also like to thank my parents for
enrolling me into a school with very good
faculty such as my Chemistry teacher,
Ramya ma’am. She has taught me well
enough to be easily equipped with the
topic that is the study of oxalate ions in
guava fruit.

3. Index
1. Certificate
2. Acknowledgement
3. Introduction to the Practical
Study
4. Practical Analysis
5. Conclusion
6. Bibliography

4. Introduction to the
Practical Study
Introduction:
Guava is sweet, juicy and light or
dark green coloured fruit. It is
cultivated in all parts of India. When
ripe, it acquires yellow colour and has
a penetrating strong scent. The fruit is
rich in vitamin C and minerals. It is a
rich source of oxalate and its content
in the fruit varies during the different
stages of ripening.
About oxalate ion:
Oxalate (C2O4
2- or (COO)2
2- ) can be
found in derivatives of oxalic acid
(COOH)2, as well as some
coordination compounds (abbreviated
as ox).

5. Oxalate occurs in many plants where
it is synthesized by the incomplete
oxidation of carbohydrates.
Some oxalate-rich plants include: fat
hen, sorrel and several Oxalis
species. Rhubarb and buckwheat are
also high in oxalic acid. More
common plants include - Star fruit,
black pepper, parsley, poppy seed,
amaranth, chard, beets, cocoa,
chocolate, nuts, berries and beans.
In this analysis, we’ll discuss the
oxalate ion concentration present in
the abundant fruit, that is, guava.

6. Practical Analysis
Aim:
To study the presence of oxalate ion
content in guava fruit at different
stages of ripening.
Requirements:
100ml measuring flask, pestle and
mortar, beaker (250ml), titration
flask, funnel, burette, weight-box,
pipette, filter paper, dilute H2SO4,
0.1N KMnO4 solution, guava fruits at
different stages of ripening.
Theory:
Oxalate ions are extracted from the
fruit by boiling up pulp with dil.
H2SO4. Then, oxalate ions are
estimated volumetrically by titrating
the solution with standard KMnO4
solution.

7. Procedure:
1. Weigh 50.0g of fresh guava and
crush it to a fine pulp using pestle-
mortar.
2. Transfer the crushed pulp to a
beaker and add about 50ml dil. H2SO4
to it.
3. Boil the contents for about 10
minutes. Cool and filter the contents
in a 100ml measuring flask.
4. Made up the volume upto 100ml by
adding distilled water.
5. Take 20ml of the solution from the
measuring flask into a titration flask
and add 20ml of dilute sulphuric acid
to it.
6. Heat the mixture to about 60°C and
titrate it against N/10 KMnO4 solution
taken in a burette. The end point is
the appearance of permanent light-
pink colour.
7. Repeat the experiment with 50.0g of
1, 2, and 3 days old guava fruit.

8. Observations:
 Weight of guava fruit each time
=50.0 g
 Volume of guava extract taken in
each titration =10 ml
 Normality of KMnO4 solution
=N/10
Guava extract
from
Burette readings Volume of
N/10
KMn04
solution
used
Initial Final
Fresh guava 150 18 132
One day old 150 15 135
Two day old 150 13 137
Three day old 150 10.8 139.2
Concordant Reading: 136.06 L

9. Calculations:
For fresh guava,
N1V1 = N2V2
(Guava extract) (KMnO4)
N1 x 10 = 1/10 x 132
Normality of oxalate,
N1=132/100 =1.32
Strength of oxalate in fresh guava
extract =Normality x Eq. mass
of C2O4
2- ion
=1.32/100 x 44g/L
= 0.581 gL-1
Similarly, calculating the strength of
1, 2 and 3 days old extract:-
1 day old: 0.594 gL-1
2 day old: 0.603 gL-1
3 day old: 0.612 gL-1

10. Results
a) The normality of oxalate ions of:
i)Fresh guava solution is= 1.32 ml
ii)Semi-ripen guava solution is = 1.37 ml
iii)Ripened guava solution is = 1.39 ml
b) The strength of oxalate ions of:
i) Fresh guava solution is = 0.58 ml
ii) Semi-ripened guava is = 0.60 ml
iii) Ripened guava is = 0.61 ml
Conclusion
The strength of oxalate ions
decreases as the guava fruit
ripens

11. Bibliography
1. Pradeep’s New Course
Chemistry
2. NCERT Textbook
3. Meritnation.com
4. Wikipedia.com