P-1 Chemical reactions and equations — Science STD 10 — Question

The reaction in which the place of the ion of a less reactive element in a compound is taken by another more reactive element by formation of its own ions, is called displacement reaction.

In the above equation when zinc dust is added to blue coloured copper sulphate solution, a colourless solution of zinc sulphate is formed and copper is deposited on zinc. The Zn²⁺ ions formed from Zn atom take the place of Cu²⁺ ions in copper sulphate, and Cu atoms formed from Cu²⁺ ion come out. It means that Zn displaces Cu from CuSO_4.