For the acid-base reactions below, prove that the equilibrium lies in the direction indicated in the reactions by comparing the pK_a values of the acids on both sides of the equilibrium arrow.

• A. a. The pK_a values of the acids on both sides of the reaction are similar, so each would have a similar amount at equilibrium.b. The pK_a value of the acid on the reactant side is greater, making it the stronger acid, so the reactant side is favored.
• B. a. The pK_a value of the acid on the reactant side is greater, making it the stronger acid, so the reactant side is favored.b. The pK_a value of the acid on the product side is greater, making it the stronger acid, so the product side is favored.
• C. a. The pK_a values of the acids on both sides of the reaction are similar, so each would have a similar amount at equilibrium.b. The pK_a value of the acid on the reactant side is greater, making it the weaker acid, so the reactant side is favored.
• D. a. The pK_a value of the acid on the product side is lesser, making it the weaker acid, so the product side is favored.b. The pK_a value of the acid on the product side is lesser, making it the weaker acid, so the product side is favored.

Answer: (C)