Hydrocyanic acid, HCN, is a weak acid. Which of the following is the correct expression for the K_a of hydrocyanic acid? A) [H₃O⁺][HCN]/[CN⁻] B) [H₃O⁺][CN⁻]/[HCN] C) [HCN]/[ H₃O⁺][CN⁻] D) [HCN][CN⁻]/[ H₃O⁺]

Question

Quizplus · Accepted Answer

The correct expression for the dissociation constant (Ka) of hydrocyanic acid (HCN) is [H3O+][CN−]/[HCN], which matches the format given in option B. This expression represents the concentration of hydronium ions and cyanide ions in the numerator and the concentration of undissociated hydrocyanic acid in the denominator.

Hydrocyanic Acid, HCN, Is a Weak Acid