The equation for the reaction of sulfur dioxide with oxygen is shown below. $\text{2SO}_2(g) + \text{O}_2(g) \rightleftharpoons \text{2SO}_3(g) \quad \Delta H = -197\,\text{kJ mol}^{-1}$ A closed container is charged with $1.0\,\text{mol}$ of $\text{SO}_2$ and $1.0\,\text{mol}$ of $\text{O}_2$, then the mixture is heated and kept at a steady temperature. When equilibrium is reached at this temperature, the equilibrium mixture contains $0.8\,\text{mol}$ of $\text{SO}_3$. Which statement is correct?
- AThe equilibrium partial pressure of $\text{SO}_2$ is greater than the equilibrium partial pressure of $\text{O}_2$.
- B$K_p$ has units of $\text{mol dm}^{-3}$.
- CAt a lower temperature, the equilibrium amount of $\text{SO}_3$ is lower than $0.8\,\text{mol}$.
- DThe mole fraction of $\text{SO}_3$ is less than $0.8$.