Question

For a reaction to occur spontaneously:

• A. $\Delta S$ must be negative
• B. $(-\Delta H+T\Delta S)$ must be positive
• C. $\Delta H+T\Delta S$ must be negative
• D. $\Delta H$ must be negative

Answer 1

The correct option is A $\Delta S$ must be negative

A spontaneous reaction is a reaction that occurs in a given set of conditions without intervention.Spontaneous reaction are accompanied by an increase in overall entropy, or disorder. If the Gibbs Free Energy is negative, then the reaction is spontaneous, and if it is positive, then it is nonspontaneous.
conclusion: hence the option (A) is correct.