Activity 1.9 Ncert Science class 10
Activity 1.9 asks us to dip iron nails in a copper sulphate solution and check the colour of the solution.
Colour of copper solution fades and nail becomes brown.
Iron in nail displaces copper from the copper sulphate solution. As a result, solution fades in colour.
This displacement reaction results in the formation of elemental copper. Elemental copper deposits on the nail and impart a brown colour to the nail.
CuSO4(aq) + Fe(s) ——-> FeSO4(aq) + Cu(s)
Note: The faded blue apperance later change to green colour because ferrous sulphate is green.