Effect of temperature change in an equilibrium reaction
As per Le Chatelier's principle, when the temperature is increased, for an exothermic reaction , the reaction shifts in the backward direction. This is clear from the van't Hoff's equation:

$$ \log\left( \frac{K'_\mathrm{p}}{K_\mathrm{p}}\right) = \frac{\Delta H^0}{2.303R}\left(\frac{1}{T_1} - \frac{1}{T_2}\right)$$ 

where $T_1$ corresponds to $K_p$ and $T_2$ corresponds to $K'_p$ . Also $T_2 &gt; T_1$.

This is because $K'_\mathrm{p}$ becomes less than $K_\mathrm{p}$.  Hence the reaction goes in the reverse direction.