Question

Aqueous solutions of the detergents are _____.
A. neutral
B. acidic
C. basic
D. amphoteric

Answer 1

Hint: To answer this question, you should recall the concept of detergents. Detergents are a type of surfactant or a mixture of surfactants that has cleansing properties in its dilute solutions.

Complete step by step answer:
Detergents generally are derivatives of alkylbenzene sulfonates, that is a family of compounds that are similar to soap but are more soluble in hard water, due to the reason that the polar part of detergents i.e. sulfonate is less likely than the polar part of soap i.e. carboxylate to bind to ions such as calcium and magnesium commonly found in hard water. They are usually available as powders or concentrated solutions.
Detergents, like soaps, work because they are amphiphilic which means it is both hydrophilic (polar) and partly hydrophobic (non-polar). This dual nature of detergents facilitates the removal of the mixture of common hydrophobic impurities like oil and grease with water. It is a fact that air is not hydrophilic, which is the reason why different detergents show varying degrees of foaming. Detergent Solutions being a common glycol base derivative are basic, their pH value tends from 9-10.

Thus, the correct option is C.

Note: Cleansing Action of Soaps and Detergents: We know that dirt and grease are oily and these oily substances do not dissolve in water. In the case of soaps, the non-polar carbon chain being lyophilic dissolves in oil and the ionic end which is the carboxylate part being hydrophilic dissolves in water. This leads to the formation of cleansing structures called micelles. The composition of soaps is sodium stearate and composition of detergents is generally sodium perborate which leads to an alkaline solution. As generally dirt is acidic, hence detergent solution must be alkaline to neutralize them and clean them.