# Are all exergonic reactions spontaneous?

Exergonic reactions have a negative $$\Delta G$$: the system loses free energy. Spontaneous reactions are also defined in the same way, as far as I know. Does this mean the two are synonymous?

There are some questions (e.g. here) asking the same question for exothermic reactions, but not all exergonic reactions are exothermic.

• That depends on conditions under which your process is taking place. If process happening under constant temperature and pressure, then negative $\Delta$G < 0 $\equiv$ spontaneous. Elif happening under constant entropy and pressure, $\Delta$H < 0 $\equiv$ spontaneous – TheLearner Feb 9 at 0:07