Question

Change in volume of the system does not alter which of the following equilibria?

• A. $N_2\left(g\right)+O_2\left(g\right)\rightleftharpoons 2NO\left(g\right)$
• B. $PC{l}_5\left(g\right)\rightleftharpoons PC{l}_3\left(g\right)+C{l}_2\left(g\right)$
• C. $N_2\left(g\right)+3H_2\left(g\right)\rightleftharpoons 2N{H}_3\left(g\right)$
• D. $S{O}_{2}C{l}_2\left(g\right)\rightleftharpoons S{O}_2\left(g\right)+C{l}_2\left(g\right)$

Answer 1

The correct option is A $N_2\left(g\right)+O_2\left(g\right)\rightleftharpoons 2NO\left(g\right)$

If a reaction does not have a same number of moles of gaseous reactant and product, change in volume of the system will alter the equilibrium existing between them.
In reaction (a), the ratio of number of moles of gaseous reactants to gaseous products is same i.e., 2 : 2, hence, change in volume will not alter the equilibrium.
In reaction (b), (c) and (d), the number of moles of reactant is not equal to number of moles of product. Thus, their equilibrium will alter when there is change in volume of the system.
Hence, option (a) is correct.