Question

why does the colour of copper sulphate solution change when iron nail is dipped in it?​

Answer 1

iron diplaces copper frm the solution of coppr sulphate because iron is more reactive than copper the colour changes from blue to pal green

Answer 2

When an iron nail is dipped in copper sulphate solution , the displacement reaction takes place . The colour of copper sulphate solution fades due to the formation of light green solution of iron sulphate .