VELAMMAL VIDHYASHRAM

MAMBAKKAM

ALL INDIA SENIOR SCHOOL CERTIFICATE

EXAMINATION

CHEMISTRY
INVESTIGATORY PROJECT REPORT
2023-2024

TO DETERMINE THE AMOUNT OF PHOSPHATE IN

THE DETERGENT

NAME : SHANMUGAM.N
ROLL.NO : 12B16
CLASS : XII SEC : B
GROUP : 2nd group
 BONAFIDE CERTIFICATE

This is to certify that this CHEMISTRY Investigatory Project on the

topic “Determination of amount of acetic acid in Vinegar ” has
been successfully completed by Bharath Kumar R of class XII
(CHEMISTRY), Roll.no…………………. at Velammal
Vidhyashram, Mambakkam for the partial fulfillment of this
project as a part of All India Senior School Certificate
Examination-CBSE, New Delhi for the academic Year 2023– 2024.

Date: ……………………

Signature of Principal Signature of the Guide

Name: Name:
—-------------------------------------------------------
Submitted for AISSCE 2023-2024, CHEMISTRY Practical
examination on ………………….

Signature of the Signature of the

Internal Examiner External Examiner

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 ACKNOWLEDGEMENT
The success of any project depends largely on people associated
with it. I would like to take this opportunity to acknowledge the
enthusiasm of all these personalities.

I hereby express my heartfelt thanks to our Senior Principal

for having given this opportunity to do the project in the biology
laboratory and for her constant encouragement.

I extend my sincere gratitude to my Biology teacher for the

valuable guidance offered to me. Her wholehearted
encouragement and constant stimulant inspiration and advice
enabled me to complete the project successfully.

I am also thankful to all our Teaching Staff and Non Teaching Staff
for their help during my course of study

I take this opportunity to express my sincere thanks to my parents

for their encouragement and support. Last but not the least I am
thankful to the almighty.

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INDEX

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 INTRODUCTION

● The goal of this project is to determine the amount of

phosphate in detergent
● The principal source of effluent phosphorus was from
phosphates used in laundry detergents . The general feeling
around the late 1960s was that many nations’ lakes and
streams were getting more polluted each day, and phosphate
detergents were the primary reason.
● Detergent is an substance, which has the ability to clean an
object. A detergent may be regarded as a surface active agent
(surfactant) particularly effective in dislodging foreign
matter from soiled surfaces and retaining it in suspension.
The term usually denotes a synthetic substance that is not
prepared by saponifying fats and oils5 . The most important
advantage of the synthetic detergents is better wetting and
cleansing action and no consumption by hard water because
of higher solubility of their Ca2+ and Mg2+ ions6.
● Phosphorus, which is an important plant nutrient, occurs
widely in the environment and in the aqueous environment
the phosphorus greatly encourages microbial growth which
is undesirable. The determination of phosphorus is therefore
of importance to chemical analysts and limnologists.

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 TITRATION
● In this experiment, you will examine various detergents for
phosphates and compare your result with the value on the
label. Record the name of the detergent, the amount of
phosphate/STPP or phosphorous indicated on the label and
the recommended amount for a load of wash.
● With this information, we can determine which detergent
analyzes for the highest or lowest phosphate/STPP (or
phosphorous) levels and which uses the most and least
phosphate/STPP (or phosphorous) per load.
● Most of the chemicals used in this experiment can be put
down the drain. However, the color developed solutions
contain heavy metals such as Vanadium (V) and
Molybdenum (Mo). It is very important to put them in the
aqueous waste container.

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 MATERIALS REQUIRED

● APPARATUS: Spectrophotometer, Erlenmeyer flask (125

ml), Two Beakers, Volumetric Flasks (4) – 50 ml, 100 ml, 250
ml, Pipettes (4) – 2 ml, 5 ml, 10 ml.

● CHEMICALS: Ammonium Vanadomolybdate Reagent,

Sulphuric Acid (H2SO4), Antifoaming Agent (Liquid DRP
Silicone Antifoam).

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 THEORY

● Phosphorus is the eleventh most abundant element on the

surface of the Earth and is mostly found as phosphate. In
nature, phosphate rocks include Fluorapatite
[3Ca3(PO4)2.CaF2], Chlorapatite [3Ca3 (PO4)2.CaCl2],
Hydroxyapatite [3Ca3(PO4)2.Ca(OH)2] and Calcium Iron
Phosphate [Ca2Fe(PO4).4H2O]. Fluorapatite is the chief ore
of Phosphorus. The phosphorus is removed from the ore by
first grinding it to remove large lumps, and then heating it in
a mixture with sand (silica, SiO2) and coke (carbon). The
reactions take place at around 1500oC using an electric arc
furnace. The key reaction is-
2Ca3 (PO4)2 + 6SiO2 + 10C → 6CaSiO3 + 10CO + P4

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● The product, which is white, can be converted into red
phosphorus by heating at 400oC for some hours. Phosphates
are added to detergents as builders in the form of Sodium
Tripolyphosphate (STPP, Na5P3O10) and Tetrasodium
Pyrophosphate (TSPP, Na4P2O7)

● The excessive use of phosphate as water softeners is

criticized by environmentalists, since it contributes to water
pollution. The phosphates in domestic waste water pass
through sewage disposal systems into rivers and lakes.
There they nourish bacteria, which grow excessively and
deplete the water of dissolved oxygen, thus killing fish. The
phosphates may also produce massive overgrowth of water
plants. When this crop of plant dies, there will be excessive
decay and putrefaction, which may also kill the fish. In
addition, excessive phosphates are known to accelerate the
natural aging of lakes (Eutrophication). They enter
waterways as runoff from agricultural lands as fertilizer and
as human and animal waste.

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● The largest source of phosphorus entering the environment
is synthetic detergents, which contain phosphate
compounds to soften water, increase the pH of water and
increase surfactant efficacy.

● In the mid 1960s, many of the nations’ rivers and lakes were
rapidly turning green and choking with aquatic plant
growth. It was later observed that the primary reason for
these deleterious changes in water quality was the high
levels of phosphorus found in domestic and municipal
sewage effluents. The principal source of effluent
phosphorus was from phosphates used in laundry
detergents.

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● Over half of the phosphorus input to the Potomac Estuary
also came from detergents in municipal and industrial
effluents. It was generally agreed that detergents accounted
for about 50% of the waste water nationwide.
● According to a study on phosphates in Germany in 1975,
some 60% of the phosphate contained in municipal sewage
originated from detergents and cleansers. As a consequence
of the partial removal of phosphate in sewage treatment
plants and the input of phosphates by other sources (human
excretion, food industry, agricultural fertilizers), the share of
detergent phosphates in surface waters was estimated to be
about 40%. This balance showed already that the reduction
of phosphates in detergent is an important but not the sole
factor in solving the eutrophication problem of surface
waters.

● Detergent is a synthetic substance, which has the ability to

clean an object which is not prepared by saponifying fats and
oils. A detergent may be regarded as a surface-active agent

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 (surfactant) particularly effective in dislodging foreign
matter from soiled surfaces and retaining it in suspension.
● Phosphates perform many functions in washing powders
and detergents. They soften hard water by binding with
calcium ions and magnesium ions. In this way, they prevent
the lime in water from depositing or settling on the textile
fibre. If the water is hard and contains dissolved lime, its
ability to dissolve soap decreases and the cleansing powder
deteriorates. Treating hard water with Trisodium Phosphate
(Na3PO4) leads to a highly soft water of approximately 0.03
mg eq dm-3 with the chemical reactions shown below –

● Moreover, phosphates stabilize the alkalinity of the

surfactants. They keep the dissolved dirt in the water and
prevent it from penetrating back into clothes.

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 PROCEDURE
There are two parts to this analysis:
1. First, the phosphate which is present as Sodium
Tripolyphosphate must be broken down (hydrolyzed) to
phosphate (a stoichiometric mixture of disodium phosphate,
Na2HPO4, and monosodium phosphate, NaH2PO4).

● Then, the resulting solution must be diluted and

treated with a reagent, Ammonium Vanadomolybdate,
to form yellow Ammonium Phosphoric
Vanadomolybdate.

2. Secondly, the intensity of the color depends on the

concentration of the phosphate and the solutions are
analyzed with a spectrophotometer by comparison to a
calibration curve.

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PREPARATION OF THE DETERGENT SAMPLE :
1. Place 1.0 g of the detergent in an Erlenmeyer flask. Add one
drop of an antifoaming agent and 25 ml of 15% Sulphuric
Acid (H2SO4). Put excess H2SO4 in the aqueous waste
container.
2. Cover the flask with an inverted beaker or watch glass.
Suspend the flask in a larger beaker of water, which contains
a few boiling chips, on a hot plate in the hood.
3. Boil the water for 30 minutes, replenishing evaporated water
as needed. Allow to cool and transfer the contents to a 250
ml volumetric flask. Rinse out the flask several times with
distilled water, pouring the rinses into the volumetric flask.
Finally, dilute the solution to the mark with distilled water.
Invert and mix thoroughly.
4. Use a 2.0 ml pipette to transfer 2.0 ml of this solution to a
100 ml volumetric flask and fill to the mark with -distilled
water. This is the dilute phosphate solution to be used in the
color development step.

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COLOR DEVELOPMENT :
1. Use a 10.0 ml pipette to measure out 10.0 ml of the dilute
phosphate solution from the detergent. Put it into a 50 ml
beaker.
2. Likewise, measure out 10.0 ml of each of the three standard
solutions prepared using detergents of various brands and
put into 50 ml beakers.
3. Use a 5.0 ml pipette to add 5.0 ml of Ammonium
Vanadomolybdate solution to each beaker. Stir the solutions
and allow 10 minutes for the color to develop
.
ANALYSIS OF THE SOLUTIONS :
1. Turn on the spectrophotometer and let it warm up for at
least 15 minutes.
2. Set the wavelength to 415 nm.
3. With nothing in the sample chamber, adjust the meter to
read 0% transmittance with the left – hand knob.
4. Insert a cuvette with distilled water. Close the cover and set
the meter to 100% transmittance with the right – hand knob
5. Measure the absorbance of each of the standard solution
prepared. Record each absorbance with the corresponding
% phosphorus listed on the label. These percentages
correspond directly to levels of phosphorus present in
detergents.

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 CALCULATION

•The total amount of phosphate ρP in mg dm-3 is

calculated according to the formula;

Where,
● A: Absorbance of the sample.
● Aq: Absorbance of the blank solution.
● f: Slope of the curve (dm3 mg-1).
● Vmax: Volume of the volumetric flask (50 ml).
● Vs: Actual volume of the sample. n = 1

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 RESULTS

● A somewhat linear relationship was found to exist between

the absorbance of the system and concentration of
phosphate (1.40 – 4.27 mg dm-3) with a straight line almost
passing through the origin. The equation of the straight line
has a correlation (R2) of 0.9963 with the equation y =
0.1235x – 0.0018.

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● The effect of the changes of ionic strength of the solution on
the absorption process of the technique was under – taken
and it was noted that ionic strength does not affect the
methodology. This can be seen from the graph of
absorbance/ionic strength. Also, the study on the effect of
pH gave the plot as shown below. This shows that there is no
need for strict pH control when an analysis of this nature is
being carried out.

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● On estimating the phosphate concentrations in each
detergent samples from various brands, it was discovered
that there were inconsistent variations in the phosphate
levels from one company to another. The detergent samples
of the brands taken are as follows –

○ Henko Matic (STPP – 7%)

○ Uni Wash (STPP – 5.1%)
○ Super Nirma Blue (STPP – 4.5%)
○ Henko Stain Champion (STPP – 4.3%)

● For high efficiency washers, it is advised to use 2

tablespoons of detergent while regular top – load washers
require up to 4 tablespoons.

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 PRECAUTIONS

1. Rinse the pipette with distilled water as soon as you are

done with it.
2. The color developed solutions must be put in the aqueous
waste container as they contain heavy metals like Vanadium
(V) and Molybdenum (Mo).
3. Excess Ammonium Vanadomolybdate should also be put in
the aqueous waste container.

CONCLUSION

● The results indicated that there is a significant variation in

terms of the phosphate levels between detergents of various
companies. This study has revealed that continuous use of
these products could result in an increase in the phosphate
levels in laundry discharges into soil, ponds, lakes and rivers.
An excessive amount of phosphorus has long been
implicated in the eutrophication of surface water bodies.
● Therefore, to promote lake/river recovery and improve
trophic status, it is recommended that phosphorus loads
entering the surface waters are reduced.

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 BIBLIOGRAPHY

1. M. Phillip, Advanced Chemistry (Physical and Industrial)

Published in South Asia by Foundation Books, New Delhi
(2003).
2. Chris Knud – Hansen, Conflict Research Consortium (1994).
3. Chemistry Textbook Part - 1 for Class - 12 – 12086 by NCERT.
4. E – Resources –
● SeminarsOnly: www.seminarsonly.com
● TSI Journals: www.tsijournals.com
● Michigan Reach Out: www.reachoutmichigan.org
● ELTE TTK – Institute of Chemistry:
www.chemistry,elte.hu
● Department of Consumer Affairs:
www.consumeraffairs.nic.in
● HERA (Human And Environmental Risk Assessment on
Ingredients of Household Cleaning Projects):
www.heraproject.com
● LabChem: www.labchem.com
● Fagerberg: www.fagerberg.dk
● Wikipedia: www.en.wikipedia.org
● Google Images: www.images.google.com

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