Compare soaps and detergents on the basis of their composition and cleansing action in hard water.

Open in App

Solution

Soaps
A soap is a water-soluble compound that is made by a process called saponification by the reaction between sodium hydroxide or Potassium hydroxide with vegetable or animal oil (fats).
They are compounds that reduce the surface tension between a liquid and another substance and therefore help in the emulsification of oils in water.
The carboxylate end of the soap molecule is hydrophilic whereas the hydrocarbon tail is hydrophobic.
Soaps form scum in hard water.
Detergents
Detergents are the potassium or sodium salts of a long alkyl chain ending with a sulfonate group.
This solubility is attributed to the fact that the sulfonate group does not attach itself to the ions present in hard water.
Commonly, anionic detergents such as alkyl benzene sulfonates are used for domestic purposes.
Detergents do not form any scum in hard water as they are soluble in hard water.
Soaps
Detergents
Soaps are potassium or sodium salts of a carboxylic acid having a long aliphatic chain attached to it.
Detergents are the potassium or sodium salts of a long alkyl chain ending with a sulfonate group.
They are surfactants and therefore help in the emulsification of oils in water
The solubility is attributed to the fact that the sulfonate group does not attach itself to the ions present in hard water.
Soaps forms scum in hard water
Detergents do not form any scum
Soaps from insoluble salts with calcium and magnesium ions and cannot be used in hard water.
Detergents can be used in both soft and hard water.
The aqueous solution of detergents does not damage delicate fabrics
An aqueous solution of soap is alkaline and damages delicate fabrics.
Examples of soaps: sodium palmitate and sodium stearate.
Examples of detergents: are deoxycholic acid and sodium lauryl sulfate.

Suggest Corrections

Similar questions

Q. (a) What is a soap? Name one soap.
(b) Describe the structure of a soap molecule with the help of a diagram.
(c) Explain the cleansing action of soap. Draw diagrams to illustrate your answer.
(d) Give the main differences between soaps and detergents.

Q. Question 34
Why are detergents better cleansing agents than soaps? Explain.

Can you use soaps and detergents to check the hardness of water ?

Q. Can you use soaps and synthetic detergents to check the hardness of water ?

Differentiate between a soap and a detergent on the basis of their chemical constituents. For cleansing action why is a detergent preferred to a soap ?

Join BYJU'S Learning Program

Soaps	Detergents
Soaps are potassium or sodium salts of a carboxylic acid having a long aliphatic chain attached to it.	Detergents are the potassium or sodium salts of a long alkyl chain ending with a sulfonate group.
They are surfactants and therefore help in the emulsification of oils in water	The solubility is attributed to the fact that the sulfonate group does not attach itself to the ions present in hard water.
Soaps forms scum in hard water	Detergents do not form any scum
Soaps from insoluble salts with calcium and magnesium ions and cannot be used in hard water.	Detergents can be used in both soft and hard water.
The aqueous solution of detergents does not damage delicate fabrics	An aqueous solution of soap is alkaline and damages delicate fabrics.
Examples of soaps: sodium palmitate and sodium stearate.	Examples of detergents: are deoxycholic acid and sodium lauryl sulfate.