Question

Hair shampoos belong to which class of synthetic detergent?
A) Anionic
B) Cationic
C) Neutral
D) None of these

Answer 1

Hint: We have to know that the detergents are the mixtures of surfactants which are used for cleansing when diluted with water. This family is more soluble in hard water unlike soap which is less soluble. These are usually amphiphilic in nature which is partly hydrophilic and partly hydrophilic in properties. A synthetic detergent works as surface active detergent.

Complete answer:
These detergents are of various types anionic, cationic, and neutral and many more. So let us study all of them in brief:
Option A) this option is incorrect as anionic detergents are alkyl benzene sulphonates in which anion is lipophilic whereas sulphonate is hydrophilic in nature. Bile acids, deoxycholic acids are the types of anionic detergents.
Option B) This option is correct as Hair shampoo belongs to the cationic detergent class as they have ammonium sulphate in centre instead of anionic sulfonate group they have they behave quaternary ammonium which is the polar end. An example of cationic detergent is cetyltrimethylammonium bromide.
Option C) this is an incorrect option as neutral detergents contain an amount of surfactants, builders or chelating agents that are used in a way to provide good wetting ability.
Option D) this is an incorrect option since we get option B as the correct option.

Note:
We have to know that a synthetic detergent works equally in soft or hard water as a surface active agent. It generally reduces the surface tension working as a non soap cleanser. Sodium n –dodecyl benzene sulphonate is an example of synthetic detergent. Detergents also have a hydrophilic nature thus it is used in shampoos.