Answer
Endothermic.
Work Step by Step
1. Count the amount of product molecules at $T_1$ and $T_2$:
$T_1$ : 2 molecules
$T_2$: 8 molecules
- The equilibrium shifted in the direction of the products when the temperature increased (from 100 $^oC$ to 200 $^oC$). Therefore, the heat is on the reactants side, so the reaction is endothermic.
