Calculate the pH of a 0.021 M NaCN solution. [K_a(HCN) = 4.9 × 10^-10] A) 1.68 B) 3.19 C) 4.69 D) 9.31 E) 10.81

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Quizplus · Accepted Answer

NaCN is a salt of a weak acid (HCN) and a strong base (NaOH). The CN⁻ ion will hydrolyze in water to form OH⁻, making the solution basic. The Kb for CN⁻ can be calculated using Kw/Ka = Kb. Then, using the Kb value, the concentration of OH⁻ can be found, and subsequently, the pOH and pH can be calculated. The pH of the solution is approximately 10.81.

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