Question:
The value of Kc for the reaction 2HI (g) ⇋ H2 (g) + I2 (g) is 1 × 10-4
At a given time, the composition of the reaction mixture is
[HI] =2 × 10-5 mol, [H2] =1 × 10-5 mol and [I2] =1 × 10-5 mol. In which direction will the reaction proceed?
Solution:
Given that Kc = 1×10-4
Kc = [H2][I2]/[HI]2
Qc expresses the relative ratio of products to reactants at a given instant.
Qc = [H2][I2]/[HI]2
= (1×10-5)(1×10-5)/(2×10-4)
Qc = 1/4 = 0.25
Here; QC >KC Reaction will proceed in reverse direction.