The signs of ΔG,ΔH,and ΔS at 25°C are shown below for three reactions. reaction ΔG ΔH ΔS
I.- + +
II.- - +
III.- - -
Which reaction could go in the reverse direction at high temperature?

Question

Quizplus · Accepted Answer

The reverse direction of a reaction is favorable at high temperature when the ΔH is positive and the ΔS is positive. This is because the positive ΔH indicates an endothermic reaction, which will be favored at higher temperatures. The positive ΔS indicates an increase in disorder or randomness, which will also be favored at higher temperatures. Among the three reactions given, only reaction III has a negative ΔS, which means the reverse direction may not be favored at higher temperatures. Therefore, the best choice is C, which is the only option where none of the reactions have a positive ΔH and a positive ΔS.

The Signs of ΔG,ΔH,and ΔS at 25°C Are Shown Below