Predicting Single Replacement Reactions || Chemistry with Dr. G

A single replacement reaction is a redox reaction in which one metal (or H) replaces another metal in a compound. These reactions do not always occur. In order for a single replacement reaction to occur, the more active metal must be the one replacing the lesser active metal that is in the compound. An example is shown below.

Mg(s) + ZnCl2(aq) → MgCl2(aq) + Zn(s)
The Mg is the more active metal as it can replace Zn2+ in ZnCl2.