Question

In a reaction, at 300k, KC is given as 2 x 10^13, then what is the value of ΔG?

(a) – 7.64 × 10^4 J

(b) – 7.64 × 10^4 J mol^–1

(c) – 7.64 × 10 J mol^–1

(d) – 7.64 × 10^4 mol^–1

This question was addressed to me in semester exam.

I'm obligated to ask this question of Relationship between Equilibrium Constant K, Reaction Quotient Q and Gibbs Energy G in portion Equilibrium of Chemistry – Class 11

Answer 1

The correct choice is (b) – 7.64 × 10^4 J mol^–1

For explanation I would say: We know that ΔG0 = – RT lnKc, where ΔG0 is the standard Gibbs free energy, R is universal gas constant, T is the temperature and KC is equilibrium constant; substituting KC as 2 x 10^13, ΔG0 = (– 8.314J mol^–1K^–1 × 300K) × ln(2×10^13); ΔG0 = – 7.64 × 10^4 J mol^–1.