Calculate the degree of hydrolysis and pH of 0.02M ammonium cyanide (NH4CN) at 298 K. [K1 of HCN = 4.99 × 10⁻¹⁰, Kb for NH4OH = 1.77 × 10⁻⁵]

Kh = 10⁻¹⁴ / (4.99 × 10⁻¹⁰ × 1.77 × 10⁻⁵) = 1.132
It can be seen that hydrolysis constant (Kh) is not small, and for calculating h, the equation used is h = √Kh / (1 + √Kh) = 1.06 / (1 + 1.06) = 0.51
Using the formula pH = pKa - log h + log (1 - h) = -log(4.99 × 10⁻¹⁰) - log (0.51) + log (1 - 0.51) = 9.3