Question

A reaction is spontaneous at low temperatures but non-spontaneous at high temperatures. Which of the following is true for the reaction?

Options

• ΔH > 0, ΔS > 0

• ΔH < 0, ΔS > 0

• ΔH > 0, ΔS = 0

• ΔH < 0, ΔS < 0

Answer 1

ΔH < 0, ΔS < 0

Explanation:

We know that ΔG = ΔH − TΔS

When ΔH < 0 and ΔS < 0 then ΔG will be negative at low temperatures (positive at high temperature) and the reaction will be spontaneous.