Question

what changes in the colour of iron nails and copper sulphate solution do you observe after keeping the iron nails in copper sulphate solution for about half an hour

Answer 1

When Iron nail (Fe) kept in Copper sulphate (CuSO4) there takes reaction between them. As Iron is more reactive tha Copper it can replace Copper from CuSO4.
Fe + CuSO4 → FeSO4 + Cu
CuSO4 is in blue Colour and FeSO4 is in light green colour.
So, there will be change in the composition and colour of the solution (from blue to light green). And decomposition of Copper layer on surface of nail.

Answer 2

Answer:

so there is change in color from blue to green