Single and double replacement

Explanation:

A single replacement or single displacement reaction is a reaction in which one substance replaces another.

            A  +   BC →   AC + B

The replacement of an ion in solution by a metal higher in the activity series is a special example of this reaction type.

The relative positions of the elements in the activity series provides the driving force for single displacement reactions.

A double replacement reaction is one in which there is an actual exchange of partners between reacting species. This reaction is more common between ionic substances;

              AB + CD → AC + BD

Such reactions are usually driven by;

it forms an anion that has a larger radius. anions have a negative charge and are larger than the original atom.