Describe in brief the cleansing action of soap. - Science

Answer in Brief

Describe in brief the cleansing action of soap.

Explain the cleansing action of soaps.

Explain the mechanism of the cleaning action of soaps.


Solution 1

Cleansing action of soaps:

The dirt present on clothes is organic in nature and is insoluble in water. Therefore, it cannot be removed by only washing with water. When soap is dissolved in water, its hydrophobic ends attach themselves to the dirt and remove it from the cloth. Then, the molecules of soap arrange themselves in micelle formation and trap the dirt at the centre of the cluster. These micelles remain suspended in the water and, thus, the dust particles are easily rinsed away by water.

Solution 2

The cleaning action of soap can be described as follows:

  • A soap molecule has a tadpole-shaped structure.
  • At one end (long, non-polar end) of the soap molecule is a hydrocarbon chain which is insoluble in water but soluble in oil.
  • At the other end (short polar end) of the soap molecule, there is a carboxylate ion which is hydrophilic, i.e. water soluble but insoluble in oil.

  • Soap, on mixed with water, forms a concentrated solution and causes foaming.
  • The long non-polar end of soap gravitates towards and surrounds the dirt and absorbs the dust in it.
  • The short polar end with the carboxylate ion repels the water away from the dirt.
  • A spherical aggregate of soap molecules is formed in the soap solution in water and is called a micelle.
  • Thus, the soap molecule dissolves the dirt and our clothes get clean.

            Formation of micelles

Concept: Soap
  Is there an error in this question or solution?
Chapter 4: Carbon and its Compounds - Exercises [Page 78]

Video TutorialsVIEW ALL [2]


Differentiate between Toilet soap and Laundry soap.

State one use of esterfication process.

A student requires hard water for an experiment in his laboratory which is not available in the neighbouring area. In the laboratory there are some salts, which when dissolved in distilled water can convert it into hard water. Select from the following groups of salts, a group, each salt of which when dissolved in distilled water will make it hard.
(A) Sodium chloride, Potassium chloride
(B) Sodium sulphate, Potassium sulphate
(C) Sodium sulphate, Calcium sulphate
(D) Calcium sulphate, Calcium chloride

What are the raw materials required for making soap in a laboratory (or at home)?

 What change will you observe if you test soap solution with a litmus paper (red and blue)? Give reason for your observation.

Which of the two is better for washing clothes when the water is hard: soap or detergent? Give reason for your answer.


Give any two differences between soaps and detergents.


Give the reason of formation of scum when soaps are used with hard water.



A student is testing water to know which is best for cleansing purposes with soaps. He would find that the cleansing action of soaps is best when he uses water obtained from

(a) rain

(b) tap

(c) hand pump

(d) pond

What is the difference between the chemical composition of soaps and detergents? State in brief the action of soaps in removing an oily spot from a shirt. Why are sops not considered suitable for washing where water is hard?

Give a scientific explanation.

Soap forms a precipitate in hard water. 

Differentiate between:
Detergents and Soaps.

Fill appropriate term in the blank:

Soap is a salt of _______ and sodium hydroxide.

Write an answer to the following question.

How will you check with the help of soap powder whether water is hard?

Write an answer to the following question.

What is meant by 'surface activity'?

Write an answer to the following question.

Name three chemicals responsible for the surface activity of various detergents.

What are the differences between Soap and synthetic detergent?

What are the similarities and differences between Bath soap and soap for washing clothes?

Explain Why Soap cannot be used in hard water.

Explain Why Synthetic detergents are superior to soap.

Explain Why Often coloured spots are formed on clothes during washing.

Soaps were originally made from ______.

The saponification of a fat or oil is done using _____ solution for hot process.

Water, coconut oil, and _______ are necessary for soap preparation.

Match the following

1. Soap C6H5 OH
2. Cement CaSO4.2H2O
3. Fertilizers NaOH
4. Gypsum RCC
5. Phenol NPK

What are the three main constituents of soap?

TFM in soaps represents ______ content in soap.

The alkaline hydrolysis of fatty acids is termed as ______

We are using ______ to remove strong stains on the clothes.

How does soap clean clothes?

______ to remove strong strains on the clothes.

______ are substances which can undergo chemical changes to produce certain materials.

______ molecules go and join with dirt and oil in the cloth.

Why do soaps not work effectively in hard water?

What are the similarities between Soap and synthetic detergent.


      Forgot password?
Use app×