Consider the following equilibrium reaction: 2AB2(g)+B2(g)→2AB3(g). ΔH=−XkJmol−1. The backward reaction will be favored by?

A. a decrease in pressure
B. an increase in pressure
C. a decrease in temperature
D. an introduction of a positive catalyst

Correct Answer: Option A

A. a decrease in pressure

Explanation

The equilibrium position is shifted to the left with a decrease in pressure in this system because the number of gaseous molecules on the right is less. (Le-Chatelier’s principle).