CHEMISTRY PROJECT
NAME : MARIA JOSHUA ANTONY .S.S
ROLL NUMBER:
STD : XII B
TOPIC : OXALATE ION IN GUAVA FRUIT
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PROJECT REPORT ON
OXALATE ION IN GUAVA FRUIT
SUBMITTED BY
MARIA JOSHUA ANTONY.S.S
2025-2026
SACRED HEART SENIOR SECONDARY
SCHOOL, CBSE
AFFILIATION NO: 1930505
TRICHY- PUDUKKOTTAI ROAD,
MATHUR, KULATHUR(TALUK)
PUDUKKOTTAI – 622515
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BONAFIDE CERTIFICATE
Certified that this is a bonafide project work done by
MARIA JOSHUA ANTONY.S.S Roll. No XII,
SACRED HEART SENIOR SECONDARY SCHOOL, CBSE,
on the topic OXALATE ION IN GUAVA FRUIT
during the year 2025 - 2026.
Submitted for AISSCE practical examination held in
CHEMISTRY at SACRED HEART SENIOR
SECONDARY SCHOOL, CBSE, Pudukkottai Road,
Mathur(post), Kulathur(Taluk), Pudukkottai -Dt
622515.
Date: Internal Examiner
PRINCIPAL External Examiner
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ACKNOWLEDGEMENT
At this outset, I express my gratitude to the
Almighty Lord for the divine guidance and wisdom
showered on me to undertake this project.
I would like to express my special gratitude to
my School Principal Rev. Sr. Deepa Joseph for the
involvement in this project by providing useful
inputs and timely suggestions.
I express my respectful and sincere thanks to
Mrs. Josephine my Chemistry Teacher and for the
guidance and help to make this project a success.
I extend my special thanks to my class students
and my friends who helped to carry out this project
in a successful manner. Hence all deserve my sincere
thanks.
My parents also played a key role in shaping up
this project nicely and I convey my special thanks to
them as well.
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INDEX
1. Introduction
o Guava: General Information
o Oxalate: Definition and Significance
o Importance of Studying Oxalate Content in Guava
2. Theory
o Extraction of Oxalate Ions
o Volumetric Estimation Using KMnO4
o Chemical Equations Involved
3. Aim of the Project
o Objective: Study the Presence of Oxalate Ions in
Guava Fruit at Different Stages of Ripening
4. Materials and Experimental Methods
o Materials
List of Materials and Equipment Used
o Experimental Methods
Step-by-Step Procedure for Extraction and
Estimation
5. Precautions
o Important Precautions to Follow During the
Experiment
6. Result and Discussion
o Observations and Data Collection
o Calculations for Different Stages of Guava Ripening
7. Conclusion
o Summary of Findings: Confirmation of Oxalate Ions
in Guava
8. References
o Sources for Further Reading and Verification
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INTRODUCTION
Guava
Guava is a common sweet fruit found in India and many other
places around the world.Guavas are plants in the Myrtle family
(Myrtaceae) genus Psidium (meaning "pomegranate" in Latin).
which contains about 100 species of tropical shrub. On ripening
it turns yellow in color. Rich in vitamin C, this fruit is a rich
source of oxalate ions whose content varies during the different
stages of ripening. Guavas have a pronounced and typical
fragrance, similar to lemon rind but less in strength.
Oxalate
It is a carboxylic acid, primarily found in plants and animals. It
is not an essential molecule and is excreted from our body,
unchanged. Our body either produces oxalate on its own or
converts other molecules like Vitamin C to oxalate. External
sources like food also contribute to the accumulation of oxalate
in our body. The oxalate present in the body is excreted in the
form of urine as waste. Too much of oxalate in our urine results
in a medical condition called, commonly referred to as kidney
stones. Diet is looked upon as preventive measure in addition to
medication to treat Kidney stones.
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THEORY
Oxalate ions are extracted from the fruit by boiling pulp with
dilute H2SO4.The oxalate ions are estimated volumetrically, by
titrating the solution with KMnO4 solution .A reagent, called
the titrant, of a known concentration (a standard solution) and
volume is used to react with a solution of the analyte or titrant,
whose concentration is not known. Using a calibrated burette or
chemistry pipetting syringe to add the titrant, it is possible to
determine the exact amount that has been consumed when the
endpoint is reached. The endpoint is the point at which the
titration is complete, as determined by an indicator. This is
ideally the same volume as the equivalence point. The volume
of added titrant at which the number of moles of titrant is equal
to the number of moles of analyte, or some multiple thereof in
the classic strong acid-strong base titration, the endpoint of a
titration is the point at which the pH of the reactant is just about
equal to7, and often when the solution takes on a persisting solid
color as in the pink of phenolphthalein indicator.
Chemical equation
2KMnO4 + 3H2SO4 → K2SO4 + 2MnSO4 + 2H2O + 4[O]
60°−70° C
HOOC − COOH. 2H2O + [O] →−−−−−→ 2CO2 + 2H2O × 5
3KMnO4 + 3H2SO4 + 5 HOOC − COOH. 2H2O → K2SO4
+ 2MnSO4 + 18H2O + 10CO2
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AIM OF THE PROJECT
To study the presence of oxalate ions in guava fruit at different
stages of ripening.
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MATERIALS AND EXPERIMENTAL METHODS
MATERIALS
• 100ml measuring flask
• Pestle and mortar
• Beaker
• Burette
• Funnel
• Weighing machine
• Filter papers
• Dil.H2SO4
• Potassium permanganate solution (KMnO4)
Guava fruits at different stages of ripening.
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EXPERIMENTAL METHODS
1. Weighed 30 g of fresh guava and crushed it to a fine pulp
using pestle and mortar.
2. Transferred the crushed pulp to a beaker and added about
50 ml dilute H2SO4 to it.
3. Boiled the content for about 10 minutes. Cooled and
filtered the content sin a 100 ml measuring flask.
4. Made up the volume 100 ml by adding ample amount of
distilled water.
5. Took 20 ml of the solution from the flask and added 20 ml
of dilute sulphuric acid to it.
6. Heated the mixture to about 60°C and titrated it against
KMnO4 solution taken in a burette till the end point had an
appearance of pink color.
7. Repeated the above experiment with 30 g of raw,semi
ripened, ripened guava fruits.
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PRECAUTIONS
1. There should be no parallax while taking measurements.
2. Spillage of chemicals should be checked.
3. Avoid the use of burette having a rubber tap as KMnO4
attacks rubber.
4. In order to get some idea about the temperature of the
solution touch the flask with the back side of your hand.
When it becomes unbearable to touch, the required
temperature is reached.
5. Add about an equal volume of dil. H2SO4 to the guava
extract to be titrated (say a full test tube) before adding
KMnO4
6. Read the upper meniscus while taking burette reading with
KMnO4 solution.
7. In case, on addition of KMnO4a brown ppt. appears, this
shows that either H2SO4 has not been added or has been
added in in sufficient amount. In such a case, throw away
the solution and titrate again.
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RESULT AND DISCUSSION
OBSERVATIONS
1. Weight of the guava fruit for each time was 30gm
2. Volume of guava extract taken for each titration was 20 ml
3. Color Changes to pink
Nature of Initial Burette Final Burette Volumeof
guava Reading Reading KMnO4
Raw 0 16.5 16.5ml
Semi ripened 0 14.5 14.5ml
Ripened 0 12 12ml
CALCULATIONS
1) For raw guava:
N1V1 = N2V2
n1M1V1=n2M2V2
M2=2/5M1V1/V2
= 0.4 x 0.02 x 20 (1/16.5)
= 0.009mol/l
where, 1-oxalate
2-KMnO4
Strength of oxalate in raw guava= 0.009 x 158 = 1.532 g/l
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2) For semi ripened guava:
Strength of oxalate in one day- old guava extract = 0.011 X 158
= 1.74g/l
3) For ripened guava:
Strength of oxalate in ripened guava= 0.013 x 158 = 2.106g/l
RESULT
(A) The Molarity of oxalate ions of:
1. Raw guava solution is = 0.009 mol/l
2. Semi-ripened guava solution is = 0.011mo1/l
3. Ripened guava solution is = 0.013mo1/l
(B) The strength of oxalate ions of:
1. Fresh guava solution is = 1.532g/l
2.Semi-ripened guava is = 1.74g/l
3.Ripened guava is = 2.106g/l
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CONCLUSION
Hence it was confirmed that guava contains Oxalate ions
or oxalic acid.
REFERENCE
• www.google.com
• www.wikipedia.com
• www.reader.google.com
• www.labs.google.com
• www.quora.com
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