For the gas phase reaction\ $\mathrm{C}_{2} \mathrm{H}_{4}+\mathrm{H}_{2} ightleftharpoons \mathr

Question

For the gas phase reaction\ $\mathrm{C}_{2} \mathrm{H}_{4}+\mathrm{H}_{2} ightleftharpoons \mathrm{C}_{2} \mathrm{H}_{6}(\Delta H=-32.7 \mathrm{kcal})$\ carried out in a vessel, the equilibrium concentration of $\mathrm{C}_{2} \mathrm{H}_{4}$ can be increased by\

Professor PC Thomas Classes · Answer

( $\mathrm{a}, \mathrm{b}, \mathrm{c}, \mathrm{d}$ ) : Since the reaction is exothermic ( $\Delta H$ is negative), any increase in temperature will favour backward reaction (Le Chatelier's principle). It will result in increase in concentration of $\mathrm{C}_{2} \mathrm{H}_{4}$ reactant. Since $\Delta n$ is negative $(1-2=-1)$ so the decrease in pressure will favour backward reaction. Removing $\mathrm{H}_{2}$ and adding $\mathrm{C}_{2} \mathrm{H}_{6}$ (product) favours backward reaction.\