Class 12 Chemistry Investigatory project .pdf

Chemistry Project
Ascorbic Acid
Class 12 Chemistry Investigatory project.
Investigatory Project
Project Report File
Class 12 Project
Ascorbic Acid Project
Science Project
Vitamin C
Vitamin C Project.
Estimation of Vitamin C in fruit and vegetable juices.

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Academic Session – 2023.24
CHEMISTRY PROJECT
“Estimation of vitamin C in fruit and vegetable juices”

Class and Section: XII A
Roll No:
Board Roll no:
Submitted by: Anonymous
Submitted to:

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CONTENTS

SR.NO. TOPIC PAGE NO.
1. Certificate 3
2. Acknowledgment 4
3. Objectives 5
4. Introduction 6-14
5. Apparatus and Chemicals Required 15
6. Theory 16-17
7. Procedure 18-21
8. Observations 22-24
9.
Analysis of data and discussion of
result
25-28
10. Conclusion 29
11. Photographs 30
12. Limitations 31
13. Bibliography 32

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CERTIFICATE

This is to certify that, I, _____, a student of class XII-A Science
Stream at Akshara international School, hereby declares that the Chemistry
project work submitted to the Chemistry teacher , _____is a record of an
original work done by me to serve as the project in Chemistry for the
AISSCE-2024 conducted by the Central Board of Secondary Education
(CBSE).



Signature of the Subject Teacher

Signature of the Principal

Signature of the External Examiner

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ACKNOWLEDGEMENT

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OBJECTIVE
To determine ascorbic acid content in fruit and vegetable
juices.

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INTRODUCTION
Ascorbic acid is known as vitamin C, but it also goes by the
chemical name’s ascorbate and antiscorbutic vitamin. The
structure of the l-ascorbic acid molecule (C6H8O6), which has
six asymmetrical carbon atoms, is similar to that of glucose.



Chemical Structure of Vitamin C

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Ascorbate, an ion of ascorbic acid, functions as an antioxidant
in living things by defending the body against oxidative
stress.

Forms of Vitamin C occurring in organisms
The central nervous system (CNS) uses vitamin C for a
variety of non-antioxidant purposes. It works as an enzymatic
co-factor in the manufacture of compounds such collagen,
carnitine, tyrosine, and peptide hormones. It is involved in
many processes in the human body, including: the
production of collagen in the connective tissue; the synthesis
of dopamine, noradrenaline and adrenaline in the nervous
system; and the synthesis of carnitine, which is important in
the transfer of energy to the cell mitochondria. A deficiency
in vitamin C causes scurvy, a disease that affected sailors in
the 16th - 18th Centuries. Furthermore, it has been
suggested that ascorbic acid could stimulate the
development of myelin in Schwann cells. Due to its high

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quantities of unsaturated fatty acids and rapid cell
metabolism, the brain is one organ that is particularly
vulnerable to oxidative stress and free radical activity. Being
an antioxidant, ascorbic acid works directly by absorbing
reactive oxygen and nitrogen species created during normal
cell metabolism.

Additionally, it serves as a cofactor in at least eight enzyme
processes. Vitamin C improves iron absorption and
detoxifying. Vitamin C supports the preservation of bone,
denin, cartilage, and healthy blood vessels. Rodents and
humans are unable to synthesize vitamin C, although the
majority of other species can.
Therefore, vitamin C consumption promotes a healthy
lifestyle.

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Vitamin C is a water-soluble (hydrophilic) vitamin. This means
it dissolves in water. It is because of the presence of several
polar -OH groups in ascorbic acid. These -OH groups will react
with the water molecules to form hydrogen bonding.
Since vitamin C is a water-soluble vitamin, the human body
cannot store it. Heat and light have the ability to degrade
vitamin C. The vitamin can be destroyed by high cooking
temperatures or extended cooking durations. Due to its
water-soluble nature, the vitamin can potentially seep
into cooking liquids and disappear if the liquids are not
consumed. Using quick heating techniques, such as stir-frying
or blanching, or using the least amount of water feasible
while cooking can help to keep the vitamin. Vitamin C

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content is highest in foods consumed raw at the height of
maturity.
The benefits and RDI (Recommended Dietary Intake) of
vitamin C, which ranges from 45 to 95 mg per day, are still up
for discussion. The liver is where you'll find the most vitamin
C, whereas muscles have the least. Animal products are not a
trustworthy source of the vitamin as animal muscle makes up
the majority of the meat consumed in the western human
diet. Compared to raw cow's milk, mother's milk contains
vitamin C. The urinary system eliminates any extra vitamin C.
Fruits that are strong in vitamin C include apricots, apples,
bananas, blackberries, cherries, kiwis, grapes, lemons, limes,
mangoes, lychees, melon, oranges, peaches, pears,
pineapples, plums, pumpkins, raspberries, strawberries,
tomatoes, and watermelons.
On the other hand, vegetables with high vitamin C content
include artichokes, asparagus, avocado, broccoli, cabbage,
maize, paprika, mushroom and spinach.

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IUPAC name:
(5R)-[(1S)-1,2-Dihydroxyethyl]-3,4-dihydroxyfuran-2(5H)-one

Acidity:
Ascorbic acid has hydroxyl groups (-OH) which can donate
protons (H+) in aqueous solutions, making it an acid.
Ascorbic acid is a vinylogous acid. The double bond ("vinyl")
transmits electron pairs between the hydroxyl and
the carbonyl. There are two resonance structures for the
deprotonated form, differing in the position of the double
bond.
The pH of ascorbic acid in water is less than or equal to 3.
Due to its extremely high acidity, ascorbic acid can have
severe adverse effects on the digestive system when
ingested on an empty stomach. Because ascorbic acid has a
low pH, calcium ascorbate (vitamin C that has been

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neutralized) was created to lessen the unfavorable effect on
the epigastric region. The pH of calcium ascorbate is 7.1.

Redox Properties:



Ascorbic acid is a strong reducing agent, due to the presence
of enediol group in its structure. It is crucial in a variety of
metabolic processes because it contributes electrons instead
of taking them.

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Tautomerism: Tautomers are isomers of a compound which
differ only in the position of the protons and electrons. The
carbon skeleton of the compound is unchanged. A reaction
which involves simple proton transfer in an intramolecular
fashion is called a tautomerism.
Although it is most stable in the enol form, ascorbic acid also
quickly interconverts into two unstable diketone tautomers
by proton transfer. To create a diketone, the enol proton is
lost and then reacquired by electrons from the double bond.
An enol reaction has occurred. 1,2-diketone and 1,3-diketone
are both potential forms.
Tautomers of ascorbic acid: (a) enol form, (b) diketone form,
and (c) dehydroascorbic acid

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Isoascorbic acid:

Structure of Isoascorbic acid
The antioxidant properties of isoascorbic acid, D-ascorbic
acid, and erythorbic acid are identical to those of ascorbic
acid and can be employed for same oenological purposes.
The solubility and appearance of this acid are identical to
those of ascorbic acid.
Optically speaking, it is the opposite of ascorbic acid.

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APPARATUS AND CHEMICALS REQUIRED
Apparatus: Burette, pipette, conical flask, beakers, measuring
flask, funnel.
Chemicals: Potassium Iodide solution.
Orange juice, Lemon Juice and Sweet Lime (Mosambi) juice.

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THEORY
Vitamin C is a water-soluble, antioxidant vitamin. It is crucial
for the production of collagen, a protein that gives shape to
blood vessels, muscles, cartilage, and bones. Additionally
helping the body absorb iron, vitamin C supports healthy
capillaries, bones, and teeth. It is one of the most widely
used vitamins ever found and the most frequent
electroactive biological substance. Blackcurrant, citrus fruit,
leafy vegetables, tomatoes, and green and red peppers are a
few examples of rich sources. The reductive abilities of
ascorbic acid are well established. As a result, it is widely
employed as an antioxidant in food and beverages. Vitamin C
serves as an essential quality indicator that adds to the
antioxidant qualities of food due to its concentration change
brought on by thermal lability.
Titration with an oxidant solution, such as potassium iodate,
dichlorophenol indophenol (DCPIP), or bromate, is a common
practice for assessing ascorbic acid. Chromatographic
techniques, especially HPLC with electrochemical detection,
have shown to be a selective and sensitive approach for
determining the amount of ascorbic acid in meals and bodily
fluids.
A different technique uses iodine and a starch indication.
Iodine combines with ascorbic acid, and once all of the

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ascorbic acid has reacted, the excess iodine forms a blue-
black combination with the starch indicator. This denotes
where the titration's end point is. Instead, ascorbic acid can
be reacted with excess iodine, then titrated with sodium
thiosulfate while utilizing starch as an indicator.

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PROCEDURE
To determine the concentration of ascorbic acid in fruits and
vegetable juices by titrating M/100 solution of Iodine against
Vitamin C juices.
Vitamin C the antioxidant
In biological systems, reactive oxidants are often produced
from metabolic processes. They have the ability to react with
other molecules (e.g., DNA), thus damaging the cell. The
body protects its cells by utilising another group of molecules
called antioxidants (to which vitamin C belongs) to reduce
(and hence detoxify) the oxidants. This experiment uses this
phenomenon in a reduction/oxidation (redox) titration,
where vitamin C reduces the orange solution of iodine to the
colorless iodide ion as shown in Figure.

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Indicators
Indicator used: Starch
I2 forms a blue complex in the presence of starch and hence
can act as its own indicator. Whilst the ascorbic acid is in
excess, the I2 which is being added from the burette is being
reduced and is decolourising. As soon as all the ascorbic acid
present has been oxidised, the added I2 will no longer be
reduced and, due to the starch that has been added, the
solution shows dark violet colouration.
Solutions Needed:
Iodine Solution:
1. To prepare Iodine solution take 3 grams of solid Iodine
and pure in a clean dry beaker.
2. Then take 2 grams of solid Potassium Iodide and add it
to the beaker.
3. Then add distilled water, and allow the potassium and
iodine to dissolve.
4. Transfer this given solution to a clean 100ml volumetric
flask and add the required amount of distilled water to
suffice. The Iodine solution is prepared.

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5. This Iodine solution has a molarity of 0.01 M
Calculations:
Weight = Molarity x Molecular weight x Volume in ml
1000

3 g of Iodine in 100ml
3g = Molarity x Molecular weight of I2 x 100ml
1000
3g = Molarity x 253.81 x 100
1000
Molarity= 1000 x 3 = 0.0118 M = 0.01 M
253.81 x 100

Starch Solution:
1. To prepare starch solution, take a spatula of salt, and
add to aqueous solution of 100ml.
Procedure:
1. Fill the 50ml burette with Iodine solution, using a funnel.

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2. Fruit juices, are extracted and filtered using cheese
cloth.
3. 5ml of fruit juice is pipetted out in a conical flask.
4. Add starch dropwise (1ml) , to the conical flask as an
indicator.
5. The solution of fruit juice, is titrated against iodine
solution.
6. The process is stopped, when the colour of the solution
in conical flask is changed from fruit juice to violet
colour.
7. Repeat for 3 concordant readings of respective juices.

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OBSERVATIONS
Observation table for Lemon Juice
Sr.
no.
Initial
Burette Reading
Final
Burette Reading
Vol of Iodine
Solution Used.
1
2
3
4
5

Concordant Reading of Volume of Iodine =

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Observation table for Orange Juice
Sr.
no.
Initial
Burette Reading
Final
Burette Reading
Vol of Iodine
Solution Used.
1
2
3
4
5

Concordant Reading of Volume of Iodine =

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Observation table for Sweet Lime (Mosambi) Juice
Sr.
no.
Initial
Burette Reading
Final
Burette Reading
Vol of Iodine
Solution Used.
1
2
3
4
5

Concordant Reading of Volume of Iodine =

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ANALYSIS OF DATA AND DISCUSSION OF RESULT





For Lemon Juice
Volume (V2)=
n1M1V1=n2M2V2
n1 = 1 n2 = 1

M1=? M2= 0.001 M

V1= 10ml V2=


Molarity of Vit C sol. M 1= n2M2V2 = 1x0.001xV2 =
n1V1 1x10

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Calculation of Vitamin C in Juice


Strength = Molarity x Molecular weight = mol/L x 176.12 g/mol

Strength = g/L

Strength = x1000mg/1000ml

Strength = mg/ml


For Orange Juice
Volume (V2)=
n1M1V1=n2M2V2
n1 = 1 n2 = 1

M1=? M2= 0.001 M

V1= 10ml V2=


Molarity of Vit C sol. M 1= n2M2V2 = 1x0.001xV2 =
n1V1 1x10






Calculation of Vitamin C in Juice

Strength = Molarity x Molecular weight = mol/L x 176.12 g/mol
Strength = g/L

Strength = x1000mg/1000ml

Strength = mg/ml

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For Sweet lime (Mosambi) Juice
Volume (V2)=
n1M1V1=n2M2V2
n1 = 1 n2 = 1

M1=? M2= 0.001 M

V1= 10ml V2=


Molarity of Vit C sol. M 1= n2M2V2 = 1x0.001xV2 =
n1V1 1x10







Calculation of Vitamin C in Juice

Strength = Molarity x Molecular weight = mol/L x 176.12 g/mol
Strength = g/L

Strength = x1000mg/1000ml

Strength = mg/ml

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RESULT
Orange juice has highest concentration of ascorbic acid, with
strength as _________ mg/ml.

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CONCLUSION
Order of fruits juices according to their concentration of
ascorbic acid:
1.
2.
3.

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PHOTOGRAPHS

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LIMITATIONS
• Use of small samples of fruit juices.
• Personal errors, i.e., Calculation errors.
• Faults in taking required measurements.
• Faulty apparatus arrangement/set-up.

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BIBLIOGRAPHY
• https://www.slideshare.net/PrakharSeth4/analysis-of-ascorbic-
acid-in-citrus-fruits
• https://www.seminarsonly.com/Engineering-
Projects/Chemistry/vitamin-c-in-fruit-juices.php
• https://scilearn.sydney.edu.au/fychemistry/LabManual/E20.pd
f
• https://byjus.com/chemistry/ascorbic-acid/
• https://www.youtube.com/watch?v=8N1wlC1c1G8