Question

What are detergents chemically? List two merits and two demerits of using detergents for cleansing. State the reason for the suitability of detergents for washing, even in the case of water having calcium and magnesium ions.

Answer 1

Detergents chemically are sodium or potassium salts of sulphonic acid of benzene or alkene. 

Merits: 

(i) They work well with hard water. 

(ii) They are more effective than soaps. 

Demerits: 

(i) They are expensive. 

(ii) Some of them having branching are non-biodegradable, therefore create water pollution. Detergents are suitable for hard water having Mg²⁺ and Ca²⁺ ions because they do not form insoluble salts with Mg²⁺ and Ca²⁺ ions.