The Ka of HCN is 4.9 × 10⁻¹⁰ . What is Kb of CN- at 298 K?
Kw = Ka × Kb = 1.0 × 10⁻¹⁴ , so Kb = (Kw/Ka) = (1.0 × 10⁻¹⁴/4.9 × 10⁻¹⁰) ≈ 2.04 × 10⁻⁵ .
Ref: NCERT Class 11 Chemistry > Chapter 6: Equilibrium > Topic: Physical Equilibrium - Solid-Liquid Gas-Liquid and Henry's Law