Investigatory ProjectOn

Chemistry

To study the foaming capacity of soaps

Submitted by: ANAGHA. CHAULKAR XII – A

K V Koliwada

CERTIFICATE

CENTRAL BOARD OF SECONDARY EDUCATION

AISSCE 2008-09

This to certify that, Ms roll no. ,

a student of class XII-A of Kendriya Vidyalaya Koliwada has completed

the investigatory project on chemistry for the purpose of practical

examination of AISSCE 2008-09 satisfactorily.

----------------------- --------------------EXAMINER PGT Chemistry

Date : / /

School Stamp

ACKNOWLEGMENT

We take this opportunity to express our sincere thanks and gratitude to Mrs. Lilly Sidharthan, Principal of K.V.Koliwada for providing the necessary facilities and infrastructure.

We further extend our thanks to Mrs. Rajni Bansal, our Chemistry teacher, for her constant guidance and support.

AIM

The objective of this project is to compare the foaming capacities of different samples of soaps.

REQUIREMENTS

1. 100 ml conical flasks with corks.2. 20 ml test tubes.3. 100 ml and 50 ml measuring cylinder.4. Test-tube stand.5. Weight box.6. Stop watch.7. Different samples of soaps.8. Distilled water.

INTRODUCTION.

Soaps are sodium or potassium salts of higher fatty acids. The higher fatty-acids may be such as stearic acid C15H35COOH, palmitic acid C15H31COOH.

A soap molecule has a lipophilic (oil soluble) part and a hydrophilic (water soluble) part. Soaps are used for washing purposes. When soap is shaken with water, it produces foam which is responsible for removal of dirt. A soap which produces more foam is more effective cleansing.

The cleansing action of soap can be explained keeping in mind that a soap molecule contain a non polar lipophilic group and a polar hydrophilic group. The dirt is held on the surface of cloths by the oil or grease which is present there. When soap is applied, the polar alkyl group dissolves in oil droplets while the polar COO-Na+ group remains dissolved in water. In the way, each oil droplet is surrounded by negative charge. This negatively charged oil droplets cannot coalesce and a stable emulsion is formed. These oil droplets containing dirt particles can be washed away with water.

Washing or cleansing capacity of soap decreases in hard water. Hard water contains Ca2+ and Mg2+ ions which interact with soap to form curdy precipitate of calcium magnesium salts of higher fatty acids.

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

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

The hardness of water can be removed by adding washing soda (Na2CO3) where by Ca2+ and Mg2+ ions get precipitated as their carbonates.

Ca2+ + Na2CO3 CaCO3 + 2Na+

Mg2+ + Na2CO3 CaCO3 + 2Na+

THEORY

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

Solutions of different soaps are prepared by dissolving their equal weights of distilled water. These solutions are shaken vigorously to produce foam and then they are allowed to stand. Times taken for the disappearance of foam in a given samples of soap, greater is its foaming capacity.

PROCEDURE

1. Weigh 0.5gm of each of the different samples provided to you.

2. Dissolve each of these weighed samples in 50ml of distilled water separately, in different conical flasks. Table the solution obtained as 1, 2, 3, 4…

3. Take 20ml test-tube and add 10ml distilled water to each of them.

4. Then add 1 ml of different soap solutions separately in different test tubes as 1,2,3,4… etc.

5. Cork test tube no.1 tightly and shake it vigorously for 1 minute.

6. Place the tube in test-tube stand and start the stop watch immediately. Note time in which the foam just disappears.

7. Similarly, note the time for the disappearance of foam in the other test tubes and record the observations.

OBSERVATION

Weight of each soap sample taken =________gm.

Volume of distilled water preparing solution of each sample =_________ml

TEST TUBE BRAND NAME OF THE SOAP

TIME TAKEN FOTHE DISAPPEARANCE OF FOAM

1.2.3.4.5.

CONCLUSION

BIBLIOGRAPHY

Comprehensive practical chemistry for class 12th.