Consider the equilibrium reaction A + 2B ⇌ 3C. When the reaction mixture is sampled prior to equilibrium being reached, it is determined that the reaction must proceed to the left for equilibrium to be reached. When the reaction mixture is sampled at equilibrium, the following concentrations are measured: [A] 0.267 mol L^-1, [B] 0.336 mol L^-1 , [C] 0.173 mol L^-1. What were the most likely concentrations of A, B, and C when the reaction mixture was sampled prior to equilibrium? A) [A] = 0.124 mol L_-1; [B] = 0.225 mol L^-1; [C] = 0.334 mol L^-1 B) [A] = 0.334 mol L^-1; [B] = 0.225 mol L^-1; [C] = 0.124 mol L^-1 C) [A] = 0.225 mol L^-1; [B] = 0.334 mol L^-1; [C] = 0.124 mol L^-1

Question

Quizplus · Accepted Answer

For the reaction to proceed to the left, the concentration of products (C) must be higher and/or the concentration of reactants (A and B) must be lower than at equilibrium. Option A has a higher concentration of C and lower concentrations of A and B compared to their equilibrium values.

Consider the Equilibrium Reaction a + 2B ⇌ 3C