Question

For a chemical reaction, the value of ΔG0 is -831.4 J/mol. Then what is the value of KC at 100 k?

(a) 1.0077

(b) 1.077

(c) 1.007

(d) 2.7

I have been asked this question in unit test.

I would like to ask this question from Relationship between Equilibrium Constant K, Reaction Quotient Q and Gibbs Energy G topic in section Equilibrium of Chemistry – Class 11

Answer 1

Right answer is (d) 2.7

The explanation is: 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 ΔG0 as  -831.4 J/mol, we get lnk = -831.4J/mol divided by -8.314J mol^–1K^–1 × 100K = 1; lnk = 1; K = e^1 = 2.7