GKFix MCQ Question

What is the ionization constant (Kb) of the conjugate base of HCN, if Ka = 4.8 × 10⁻⁹ at 298 K?

• A. 2.08 × 10⁻⁶
• B. 4.8 × 10⁻⁹
• C. 1.0 × 10⁻¹⁴
• D. 4.8 × 10⁻⁶