For the reaction N2(g)+3H2(g)⇌2NH3(g),ΔH=−93.6 kJ mol−1. The concentration of H2 at equilibrium will increase if
The volume of the system is decreased
The choices a, c and d will decrease the concentration of H2. The choice b is correct since decreasing volumewill cause the reaction to move in the direction of increasing volume, i.e., towards the larger number ofgaseous species.