Question-24 Which of the following set of thermodynamic conditions is true for the reaction to be spontaneous at high temperature?
(A) \Delta H<0\ and\ \Delta S<0
(B) \Delta H>0\ and\ \Delta S>0
(C) \Delta H<0\ and\ \Delta S>0
(D) \Delta H>0\ and\ \Delta S<0
Answer : (B)
Explanation:
When both ΔH and ΔS are positive, then ΔG is positive at low temperature but negative at high temperature.
Therefore, reaction is nonspontaneous at low temperature but becomes spontaneous at high temperature.