A metal displacement reaction is one where a less reactive metal in a compound is replaced by a more reactive metal.
In general, a more reactive metal can displace a less reactive metal from its compound. This concept is used in the thermite reaction (also known as the Goldschmidt process) for preparing small quantities of metallic iron.
2Al (s) + Fe2O3 (s) → Al2O3 (s) + 2Fe (s)
Question
What do you observe when you place a strip of magnesium in a beaker containing dilute aqueous copper sulphate?
Answer
The blue solution turns colourless with pink deposits at the bottom of the beaker.
Mg (s) + CuSO4 (aq) → MgSO4 (aq) + Cu (s)