7.4 Single Replacement and the Activity Series

Notes

In a single replacement reaction, one element replaces another in a compound: $\text{A} + \text{BC} \rightarrow \text{AC} + \text{B}$.

• A metal replaces a less active metal or hydrogen. A halogen replaces a less active halogen.
• The activity series ranks metals from most to least active: Li, K, Ba, Ca, Na, Mg, Al, Zn, Fe, Ni, Sn, Pb, (H), Cu, Ag, Au.
• A metal can replace only metals below it. Metals above H react with acids to release $\text{H}_2$.
• Halogens: $\text{F}_2 > \text{Cl}_2 > \text{Br}_2 > \text{I}_2$.
• Example: $\text{Zn} + \text{CuSO}_4 \rightarrow \text{ZnSO}_4 + \text{Cu}$ works because Zn is above Cu. $\text{Cu} + \text{ZnSO}_4$ gives no reaction.