Answer
The forward process of this reaction is endothermic.
Work Step by Step
Analyzing the informations from the question, we can see that, with the raise of the temperature, the ion-product constant increases.
The equation for the ion-product constant is:
$[H^+] * [OH^-] = K_w$
Which means that, the raise of the constant means the increase of $[H^+]$ and $[OH^-]$ production.
Therefore, the increase of heat benefits the forward reaction. Which means that it is a endothermic reaction.
