Question

Which of the following circumstances will result in a reaction that is spontaneous at all temperatures?

Answer 1

Negative enthalpy change and positive entropy change. I am sure that's the answer!

Answer 2

Answer: negative enthalpy change and positive entropy change

Explanation:-

According to Gibb's equation:

$\Delta G=\Delta H-T\Delta S$

$\Delta G$ = Gibbs free energy

$\Delta H$ = enthalpy change

$\Delta S$ = entropy change

T = temperature in Kelvin

$\Delta G$= +ve, reaction is non spontaneous

$\Delta G$= -ve, reaction is spontaneous

$\Delta G$= 0, reaction is in equilibrium

Thus when $\Delta H$ = -ve

$\Delta S$ = +ve

$\Delta G=(-ve)-T(+ve)$

$\Delta G=(-ve)(-ve)=-ve$  

Reaction is spontaneous at all temperatures.