The equations are as follow,
A) HCN (aq) + H₂O (l) ↔ H₂CN⁺ (aq) + OH⁻ (aq)
B) H₂O (l) ↔ H⁺ (aq) + OH⁻ (aq)
C) HCN (aq) ↔ H⁺ (aq) + CN⁻ (aq)
D) HCN (aq) + H₂O (l) ↔ CN⁻ (aq) + H₃O⁺ (aq)
E) HCN (aq) ↔ H⁻ (aq) + CN⁺ (aq)
Answer:
Option-D is the correct answer.
Explanation:
When hydrogen cyanide is added in water it partially ionizes as follow,
HCN (aq) + H₂O (l) ↔ CN⁻ (aq) + H₃O⁺ (aq)
Being weak acid it fails to completely dissociate into H⁺ and CN⁻ ions. In this reaction water is acting as a Bronsted Lowery Base and picks proton from from HCN and converts into conjugate acid (i.e. H₃O⁺), while, HCN converts into conjugate Base (i.e. CN⁻).
