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A double decomposition reaction effected by water, according to the general equation

XY + H2O → XOH + YOH

If XY is a salt of a weak acid or a weeak base, the hydrolysis is reversible, and affects the pH of the solution (see buffer). Reactive organic compounds such as acid chlorides and acid anhydrides are rapidly hydrolyzed by water alone, but others require acids, bases, or enzymes as catalysts (as in digestion).

Industrial hydrolysis processes include the alkaline saponification of oils and fats to glycerol and soap, and the acid hydrolysis of starch to glucos.

Hydrolysis is the reverse of a condensation reaction. A water molecule is added to the point in a polymer where two subunits are joined, causing the polymer to split apart at that point.

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