Chemistry - Chemical Equilibrium Question with Solution | TestHub

The reaction is: ${\mathrm{CaCO}}_3(\mathrm{s})\rightleftharpoons \mathrm{CaO}(\mathrm{s})+{\mathrm{CO}}_2(\mathrm{g});{\Delta }_{\mathrm{r}}\mathrm{H}=+\mathrm{ve}$

This is a heterogeneous equilibrium. The concentrations of pure solids (${\mathrm{CaCO}}_3$ and $\mathrm{CaO}$) do not affect the equilibrium position.

A. Incorrect. Adding ${\mathrm{CaCO}}_3(\mathrm{s})$ does not shift the equilibrium.

B. Incorrect. Adding $\mathrm{CaO}(\mathrm{s})$ does not shift the equilibrium.

C. Correct. ${\Delta }_{\mathrm{r}}\mathrm{H}=+\mathrm{ve}$ (endothermic). Increasing temperature shifts equilibrium forward, increasing ${\mathrm{P}}_{{\mathrm{CO}}_2}$.

D. Incorrect. Adding ${\mathrm{CaCO}}_3(\mathrm{s})$ does not change ${\mathrm{P}}_{{\mathrm{CO}}_2}$ at constant temperature.