Question

(a) Why do acids not show acidic behaviour in the absence of water?
(b) Why does an aqueous solution of an acid conduct electricity?
(c) Why does distilled water not conduct electricity whereas rain water does?

Answer 1

(a) The acidic behaviour of a substance is due to the presence of H⁺ ions. As acids dissociate into their ions only in the presence of water, the acidic character of acids cannot be seen in the absence of water.

(b) Acids dissociate to release H⁺ ions and an anion, when dissolved in water. When electric current is passed through an aqueous solution, the ions start moving toward oppositely charged terminals of the battery, henceforth, conducting electricity.

(c) Distilled water is the purest form of water. The process of distillation makes the water free from all the ionic species, whereas rainwater consists of plenty of impurities. Thus, it contains numerous ions such as H⁺, CO₃^-, SO₄^2- etc. Therefore, rainwater conducts electricity.