Consider the reaction
A\(_{(s)}\) + 2B\(_{(g)}\) → 2C\(_{(aq)}\) + D\(_{(g)}\)
What will be the effect of a decrease in pressure on the reaction?

A.

the equilibrium will shift

B.

rate of forward reaction will increase

C.

rate of backward reaction will increase

D.

rates of forward and backward reaction are not affected

Correct answer is C

Given: The equation below
A\(_{(s)}\) + 2B\(_{(g)}\) → 2C\(_{(aq)}\) + D\(_{(g)}\)

According to Le Chatelier's Principle:

Pressure changes affects only the gaseous reactants and products
There must be different amount of gaseous particles on both sides.

Generally; a decrease in the pressure shifts the equilibrium position in favor of the side with larger volume of gases.

I.e  rates of backward reaction.