Question

Soaps are:
a.) Sodium or potassium salts of higher fatty acid.
b.) Ester of higher fatty acids.
c.) Glycerides of fatty acids.
d.) Hydrides of fatty acids.

Answer 1

Hint: In this question use the basic definition of surface active or surfactants. These refers to the chemical substances which concentrate at the surface of the solution and form surface films, they reduce surface tension of the solution and help in removing the dirt and dust by emulsifying grease.

Complete step-by-step answer:
Soaps are sodium potassium salts of higher fatty acid that is lauric acid $({C_{11}}{H_{23}}COOH)$, palmitic acid $({C_{15}}{H_{31}}COOH)$, stearic acid $({C_{17}}{H_{35}}COOH)$,etc. Soaps are formed by heating fat or oil (glyceryl esters of fatty acids) with aqueous sodium hydroxide solution, however this reaction is called saponification.
During the process of hydrolysis, the esters of fatty acids are hydrolysed and the soap is obtained in the colloidal form moreover it floats in solution as crude. It is precipitated from the solution by adding solution and by adding sodium chloride. When the soap is removed from the solution then a precipitate solution is left behind and it is termed as lye. It contains glycerol which can be obtained by fractional distillation. Therefore, only sodium and potassium soaps are soluble in water and it is used for cleaning purposes. Generally, potassium soaps are softer to skin than sodium soaps. These are prepared by hydrolysis of oils and fats with aqueous potassium hydroxide instead of sodium hydroxide.
Soap is known for its property of being a very good cleansing agent . Soaps are generally 100% biodegradable and provide no harm to nature. As we know that all soaps are prepared by boiling fats and oil with a suitable soluble hydroxide. However, different raw materials can be used to make different soaps. For example: toilet soaps, floating soaps, transparent soaps, medicated soaps, shaving soaps, laundry soaps, soap chips ,etc.. The disadvantage of soaps is that it cannot be used in hard water and also cannot be used in acidic solution.
Therefore, from the following options given in the question, the option (A) is the correct answer.

Note: Soaps have relatively weak cleansing action. Thus, the molecules of a surfactant contain two characteristic groups; one of which is water soluble (hydrophilic) and the other in soil soluble (lyophilic or lipophilic). These are two types:- soap, synthetic detergents.