When iron nails are added to an aqueous solution of copper sulphate, a chemical change occurs, which of the following is not true about this reaction ?

The correct option is D Iron nails dissolve completely

$Fe\left(s\right)+CuS{O}_4⟶Cu\left(s\right)+FeS{O}_4$

When an iron nail is dipped in copper sulphate solution, a brown coating of copper is formed on the surface of iron and the colour of copper sulphate solution changes from blue to light green. This reaction shows that iron is more reactive than copper as it displaces copper from its solution and iron passes into solution as $F{e}^{2+}$ ions and ferrous sulphate solution is formed.