Which of the following equilibria remains unaffected by a change in pressure (or volume)?

Options

A. `2NOCl(g)hArr2NO(g)+Cl_2(g)`
B. `H_2(g)+CO_2(g)hArrH_2O(g)+CO(g)`
C. `2PbS(s)+3O_2(g)hArr2PbO(s)+2SO_2(g)`
D. `PCl_5(g)hArrPCl_3(g)+Cl_2(g)`

Answer

B

Explanation

If there is no change in the total number of moles of gases in a reaction, a pressure (volume) change does not affect the position of equilibrium, i.e., Q is unchanged bythe volume (or pressure) change. In reaction (2), the number of moles of gas products is equal to the number of moles of gas reactants. Thus, a change in pressure has no effect on the equilibrium.