TO STUDY THE

FOAMING
CAPACITY OF
SOAPS
Study of the foaming capacity of soaps.

By-
Nandini Mondal

XI-A, 18
 CERTIFICATE
This is to certify that “Nandini Mondal” student of class
11th A
has successfully completed their Chemistry Project on the
topic
“To study the foaming capacity of soaps” under the
guidance of
the respected teacher.
Teacher’s Signature- ________________

ACKNOWLEDGEMENT
I would like to express my special thanks of gratitude to
my teacher who gave me the golden opportunity to do
this wonderful project of Chemistry on “To study the
foaming capacity of soaps”, who also helped me in
completing my project. I came to know about so many
things I am really thankful to them. Secondly, I would also
like to thank my parents and friends who helped me a lot
in finalizing this project within the limited time frame.
 INDEX
S.NO. TOPIC PAGE No.

1. Cover page 1

2. Certificate 2

3. Acknowledgement 3

4. Index 4

5. Introduction 5-6

6. Objective of 7
project

7. Experiment 1 7-9
 8. Experiment 2 9-11

9. Bibliography 12

INTRODUCTION
Soaps are sodium or potassium salts of higher fatty acids like stearic,
palmitic and oleic acids can be either saturated or unsaturated. They
contain a long hydrocarbon chain of about 10-20 carbon with one
carboxylic acid group as the functional group. A soap molecule a
tadpole shaped structure, whose ends have different polarities. At one
end is the long hydrocarbon chain that is non-polar and hydrophobic,
i.e., insoluble in water but oil soluble. At the other end is the short
polar carboxylate ion which is hydrophilic i.e., water soluble but
insoluble in oil and grease.

When soap is shaken with water it becomes a soap

solution that is colloidal in nature. Agitating it tends to
concentrate the solution on the surface and causes
foaming. This helps the soap molecules make a
unimolecular film on the surface of water and
to penetrate the fabric. The long non-polar end of a soap
molecule that are hydrophobic, gravitate towards and
surround the dirt (fat or oil with dust absorbed in it). The
short polar end containing the carboxylate ion, face the
water away from the dirt. A number of soap molecules
surround or encircle dirt and grease in a clustered
structure called 'micelles', which encircles such particles
and emulsify them.

Cleansing action of soaps decreases in hard water. Hard

water contains calcium and magnesium ions which
react with sodium carbonate to produce
insoluble carbonates of higher fatty acids.

2C17H35COONa + Ca2+ (C17H35COO)2Ca + 2Na+

2C17H35COONa + Mg2+ (C17H35COO)2Mg + 2Na+

This hardness can be removed by addition of Sodium

Carbonate.

Ca2- + Na2CO3 CaCO3 + 2Na+

Mg2+ + Na2CO3 MgCO3 + 2Na+

OBJECTIVE OF PROJECT
The objective of this project is to compare the foaming
capacities of different samples of soaps and to study the
 effect of addition of washing soda (Na2CO3) on the
foaming capacity of a soap.

EXPERIMENT-1

AIM:
Compare the foaming capacities of different samples of
soaps.

REQUIREMENTS:
100 ml conical flasks with corks, 20 ml test-tubes,100 ml
measuring cylinder, 50 ml measuring cylinder, test-tube
stand,weight box and stop-watch. Different samples of
soaps and distilled water.

THEORY:
There is no quantitative method for the determination of
foaming capacity of a soap. However, the foaming
capacity of different soaps can be compared qualitatively
by the following way.

Solutions of different soaps are prepared by dissolving

their equal weights in equal volumes of distilled water.
These solutions are shaken vigorously to produce foam
and then they are allowed to stand. Time taken for the
disappearance of foam are measured for different
samples. Longer the time taken for the disappearance of
foam in a given sample of soap, greater is its foaming
capacity.

PROCEDURE:
 1)Weigh 0.5 g of each of the different samples of soap
provided to you.
2)Dissolve each of these weighed samples in 50 ml of
distilled water separately, in different conical flasks.
Label the solution obtained as 1, 2, 3, 4,......
3)Take 20 ml test-tubes (equal to the no. of soap
samples to be tested) and add 10 ml distilled water
to each of them. Then add 1 ml of different soap
solutions separately in different test-tubes and
correspondingly mark the test-tubes as 1, 2, 3, 4 etc.
4.
4)Cork test-tube no. 1 tightly and shake it vigorously
for 30 seconds. Place the tube in test-tube stand and
start the stop-watch immediately. Note time in which
the foam just disappears.
5)Similarly, note the time for the disappearance of
foam in the other test-tubes and record the
observations.

OBSERATIONS:
Weight of the each soap sample taken 0.5 gm
Vol of distilled water taken for preparing solution of each
sample 50 ml

Test tube no. Brand name of Time taken for

the soap the
disappearance
of foam (in min)
1. Dettol 10
2. Lux 15
3. No.1 20
4. Breeze 22
5. Lifebuoy 25
CONCLUSION:
The soap for which the time taken for the disappearance
of foam is highest has maximum foaming capacity and
is the best quality soap among the soaps tested.

EXPERIMENT-2
AIM:
Study the effect of addition of sodium carbonate (washing
soda) on the foaming capacity of a soap.

REQUIREMENTS:
100 ml conical flasks with corks, 20 ml test-tubes,100 ml
measuring cylinder, 50 ml measuring cylinder, test-tube
stand,weight box and stop-watch. Different samples of
soaps and distilled water.

THEORY:
Calcium and magnesium ions present in the tap water
interfere in the foaming capacity of a soap. These ions
combine with soap and form the insoluble salts which get
precipitated.

2C17H35COONa + Ca2+ (C17H35COO)2Ca + 2Na+

(Soap) (ppt.)

Therefore, in the presence of these ions the foaming

capacity of soap decreases.
When Na2CO3 is added to tap water, calcium and
magnesium ions get precipitated as their carbonates.
Therefore, in the presence of Na2CO3.
 Ca2+ + Na2CO3 CaCO3 + 2Na+

Mg2+ + Na2CO3 MgCO3 + 2Na+

foaming capacity of water increases. In order to

demonstrate this the foaming capacity of the given
sample of soap will be determined first in distilled water,
then in tap water and finally in tap water containing
sodium carbonate.

PROCEDURE:
1)Weigh 0.5 g of the given sample of soap and dissolve
it in 50 ml of distilled water taken in a conical flask.
2)Take three test-tubes and label them as 1, 2 and 3.
To the first tube add 10 ml of distilled water, to the
second add 10 ml of tap water and to the third add 5
ml of tap water and 5 ml of 0.10 M Na2CO3 solution.
3)To each of the three test-tubes add 1 ml of soap
solution.
4)Cork test-tube No. 1 tightly and shake vigorously for
30 seconds. Place the test-tube in test-tube stand
and start the stop-watch immediately. Note the time
in which the foam just disappears.
5)Similarly, note the time for the disappearance of
foam in the remaining two test-tubes and record the
observations.

OBSERVATIONS:
Weight of soap taken = 0.5 g
Volume of distilled water taken for preparing solution =
50 ml.

Test tube no. Water used Vol of soap Time taken for
solution the
 disappearance
of foam
1. 10ml distilled 1ml
water
2. 10ml tap 1ml
water
3. 5ml tap 1ml
water+5ml
M/10 Na2CO3
sol

CONCLUSION:
Foaming capacity of soap is maximum in distilled water.
The foaming capacity of tap-water increases on the
addition of sodium carbonate.
 BIBLIOGRAPHY
 https://www.scribd.com/document/371649677/
Investigatory-file-on-foaming-capacity-of-soaps.
 Comprehensive Practical Chemistry.
 www.wikipedia.co.in