If, at a given temperature, the equilibrium constant for the reaction H₂(g) + Cl₂(g) 2HCl(g) is 4.2, then the equilibrium constant for the reaction HCl(g) (1/2)H₂(g) + (1/2)Cl₂(g) can be represented as

Question

Quizplus · Accepted Answer

First, let's write the balanced equation for the reaction given: H₂(g) + Cl₂(g) ⇌ 2HCl(g) Now, let's use the relationship between equilibrium constants for the forward and reverse reactions: Kc (forward) = 1/Kc (reverse) where Kc is the equilibrium constant. For the reverse reaction, which we need to find the equilibrium constant for, we can write: HCl(g) ⇌ (1/2)H₂(g) + (1/2)Cl₂(g) And use the equation above: Kc (reverse) = 1/Kc (forward) Kc (reverse) = 1/4.2 = 0.238 Note that the coefficients in the balanced equation are used to take into account the stoichiometry of the reaction, which is important for finding the equilibrium constant. The answer is therefore (C) 0.49, which is the closest choice to the value we calculated.

If, at a Given Temperature, the Equilibrium Constant for the Reaction