If the K_b for CN⁻ is 1.6 × 10⁻⁵, K_a for HCN is 6.3 × 10⁻¹⁰.

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Quizplus · Accepted Answer

The K_b for CN⁻ is 1.6 × 10⁻⁵, and the K_a for HCN is 6.3 × 10⁻¹⁰. The relationship between K_b and K_a for a conjugate acid-base pair is K_b × K_a = K_w, where K_w is the ion product constant for water (1.0 × 10⁻¹⁴). Therefore, K_b × K_a = (1.6 × 10⁻⁵) × (6.3 × 10⁻¹⁰) = 1.0 × 10⁻¹⁴, which is equal to K_w. This confirms that CN⁻ and HCN are a conjugate acid-base pair.

If the Kb for CN− Is 1

If the K_b for CN⁻ Is 1