Question

Identify a conjugate pair in the equation: NH3 + H2O \(\rightleftharpoons\) NH4^+ + OH^–.

(a) ammonia and water

(b) water and hydroxide ion

(c) ammonium ion and hydroxide ion

(d) ammonia and hydroxide ion

The question was posed to me in class test.

My question is taken from Equilibrium in section Equilibrium of Chemistry – Class 11

Answer 1

The correct option is (b) water and hydroxide ion

For explanation I would say: According to Bronsted concept of acids and bases, the two conjugate pairs in the above-given equation NH3 + H2O \(\rightleftharpoons\) NH4 + OH^– are Ammonia – ammonium Ion and water – Hydroxide ion. Here acids are water and ammonium ion.