Paheli prepared a blue coloured solution of copper suplhate in beaker a and placed an iron in it. Boojho prepared a yellowish green solution of ferrous sulphate in beaker B and placed a copper wire in it. What changes will they observe in the two beakers after an hour?

In Beaker A we will observe a reddish brown colour of copper on the iron nail and blue coloured solution of copper sulphate will become yellowish green due to the formation of iron sulphate. This is because iron is more reactive than copper and it displaces copper from its salt solution of copper sulphate. In beaker B, no change is observed because copper being less reactive does not displace iron which is more reactive than copper from its ferrous sulphate solution.