In a displacement reaction, what happens?

• A. A less reactive metal displaces a more reactive metal
• B. No reaction occurs
• C. A more reactive metal displaces a less reactive metal.
• D. The compound boils

Answer: (C)

In metal displacement reactions, a more reactive metal can push a less reactive metal out of its compound in solution. This happens because the more reactive metal tends to lose electrons more readily. When it’s placed in a solution containing ions of a less reactive metal, electrons flow from the more reactive metal to those metal ions. The more reactive metal becomes a positive ion, and the less reactive metal ions are reduced to solid metal, which often appears as a deposit.

For example, if you put zinc metal into a solution of copper ions, zinc donates electrons to the copper ions: zinc goes into solution as Zn2+, while copper metal is deposited. The overall effect is that the more reactive metal displaces the less reactive metal from its compound.

If a metal is less reactive than the metal in solution, no displacement occurs, which is why the rule is that a more reactive metal displaces a less reactive metal.