The reaction of gaseous $H_2$ and liquid $B{r}_2$ to give gaseous $HBr$ has $H=-72\mathrm{.}8k\frac{J}{m}ol$ and $S=114\frac{J}{\text{m}\text{o}\text{l}*K}.$

a$.$ Does entropy increase or decrease in this process? Is this process spontaneous at all temperatures? Explain.

b$.$ What is the value of $G$ for the reaction at $300K?$

c$.$ What is the difference between an exothermic reaction and an exergonic reaction?