Define retention.

Explanation

If relative configuration of atoms or groups around the chiral centre is an optically active compound remains the same before and after the reaction, then the reaction is said to proceed by retention of configuration, for example,

In general, if during a reaction, no bond to the chiral centre is broken product will have the same general configuration of groups around the chiral .centre as that of the or reactant. Such as reaction is said to proceed with retention of the configuration. For example,