26. NCERT Exemplar XVII

 

Take about 50 mL of water in a beaker and dissolve 5 g of copper nitratecopper sulphatecopper chloridecopper acetate in it to obtain copper sulphate solution (which is blue in colour). Put a clean iron nail in this solution and keep the beaker undisturbed for some time.

We will find that the brownyellowgreenblue colour of copper sulphate solution starts fading gradually, and the iron nail gets covered with a red-brown layer of copper metal. It is because iron is more reactiveless reactiveless activemore active than copper, so it displaces copper metal from its solution of copper sulphate.

It is the copper metal set free from its compound which forms a red-greenbrown-redred-brownyellow-green layer on the surface of iron nails.

 

This shows that iron is less activemore activeless reactivemore reactive than copper.

 

Copper sulphate + Iron $\to$ Iron sulphate + Copper