Question

When an object made of material A is kept immersed in the blue coloured solution B,

then a chemical change takes place to form a green coloured solution C and a brown layer

of substance D is deposited on the object . A is used for making nails and D is used for

making electric wires.​

Answer 1

Blue colour of copper sulphate solution changes into green colour & then iron nail acquires a brownish look. This is because that iron is more reactive than copper.

Fe+CuSO 4 →FeSO 4+Cu

In this reaction, iron displaces copper from CuSO 4 solution.