Question

Soaps are sodium salts of:
A. mineral acids
B. fatty acid
C. bases
D. carbonic acid

Answer 1

Hint: To find the answer of this question you can use the basic definition of the surfactants or surface active. The surfactants refers to those chemical substances which concentrate at the surface of the solution and thus form the surface films, they tend to reduce the surface tension of the solution and help in the removal of dirt and the dust through emulsifying grease.

Complete answer:
From your chemistry lessons you have learned about the soaps and their composition. Soaps are the sodium or the potassium salts of the higher fatty acids the acid are palmitic acid $({{C}_{15}}{{H}_{31}}COOH)$, lauric acid $({{C}_{11}}{{H}_{23}}COOH)$ and stearic acid $({{C}_{17}}{{H}_{35}}COOH)$, etc.
The formation of soaps is done by heating the oil (glyceryl esters of fatty acids) or fats with the aqueous solution of sodium hydroxide and this process is known as saponification.
So, during the hydrolysis process, the esters of fatty acids get hydrolysed and the soaps are obtained in the form of colloids moreover it tends to float in the solution in the form of crude. Then it is precipitated from the solution through adding sodium chloride and the solution.
After the removal of soap from the solution they left behind a precipitate solution that is known as lye. Lye contains glycerol in it which is obtained through fractional distillation. Hence we can say that only potassium and sodium soaps are soluble in the water and are used for the cleaning purposes. Therefore sodium salts are made up of higher fatty acids.

Thus the correct option will be (B).

Note: The cleansing action of the soaps are relatively weak. Therefore the molecules present at the surfactants contain two groups one of which is soil soluble (lyophilic or lipophilic) and the other one is water soluble (hydrophilic). These are of two types:- synthetic detergent and the soaps. The potassium soaps are much softer to skin than the sodium salts .