Which of the following statements is true.
a. all spontaneous processes are exothermic.
b. all non spontaneous processes are endothermic
c. all spontaneous processes release free energy.
d. entropy always increase in a spontaneous process.

The correct answer is Option C.

Explanation:

Spontaneous reactions are defined as the reactions in which Gibbs free energy change is always negative and when Gibbs free energy change is positive, the reactions are known as non-spontaneous reactions.

Exothermic reactions are the reaction in which enthalpy change is negative and when the enthalpy change is positive, they are known as endothermic reactions.

Spontaneous reactions can be exothermic as well as endothermic.

It is not always that when entropy increases, reaction will be spontaneous. There are cases when the entropy is getting decreased but the reaction is still spontaneous.

Hence, the correct answer is Option C.

answerlinnaeus;