If gaseous iodine is warmed with hydrogen at $450^{\circ}\text{C}$, the system reaches equilibrium. $\text{H}_2(g) + \text{I}_2(g) \rightleftharpoons 2\text{HI}(g) \qquad \Delta H = +53\ \text{kJ mol}^{-1}$ $\text{H}_2$: colourless, $\text{I}_2$: purple, $\text{HI}$: colourless. Which alteration in conditions would make the purple colour of the equilibrium mixture less intense?
- Adecrease in pressure
- Bdecrease in temperature
- Cincrease in pressure
- Dincrease in temperature