In chemistry, is the reverse reaction of a spontaneous reaction always a non-spontaneous reaction, and vice versa? In other words, if your forward reaction is spontaneous, will your reverse reaction be non-spontaneous?

Watchkeeper

No, not necessarily. For example, mix an acid such as ethanoic acid with an alcohol such as ethanol and you will get an ester (in this case ethyl ethanaoate) and water. However, the reaction is not complete and an equilibrium mixture of the four substances is formed. The reaction does not stop, but the rate of the forward reaction (esterification) is equal to the rate of the reverse reaction (ester hydrolysis or saponification). Both forward and reverse reactions are spontaneous and occurring continuously. The position of equilibrium depends on the conditions of reaction. http://www.chemguide.co.uk/organicprops/alcohols/esterification.html Jun 15 09, 10:04 AM