Areaction is non-spontaneous at any temperature whendelta h is positive and delta s is positivedelta h is positive and delta s is negativedelta h is negative and delta s is negativedelta h is negative and delta s is positive

Delta H is positive and Delta S is negative

Explanation:

The expression for the standard change in free energy is:

Where,  

is the change in the Gibbs free energy.

T is the absolute temperature. (T in kelvins)

is the enthalpy change of the reaction.

is the change in entropy.

For a reaction to be non spontaneous, it means that:-

Thus,

For the above conditions to satisfy, must be positive and must be negative.