Question

What is the relation between KP and KC?

(a) KC = KP

(b) KC = KP(RT)

(c) KC = KP(RT)^Δng

(d) KP = KC(RT)^Δng

This question was posed to me in quiz.

I need to ask this question from Homogeneous Equilibria topic in chapter Equilibrium of Chemistry – Class 11

Answer 1

Correct answer is (c) KC = KP(RT)^Δng

The explanation is: For example, take the reaction 2HBr(g) \(\leftrightarrow\) H2(g) + Br2(g), KC = [H2][Br2]/[HBr]^2; KP = [pH2][pBr2]/[pHBr]^2, where pH2 = [H2]RT, pBr2 = [Br2]RT and [pHBr] = [HBr]RT. So we can say that KC = KP(RT)^Δng, where Δng = moles of products – moles of reactants which are in gaseous state only.