Question

a) why iron nails are kept in copper sulphate solution?

b) why dilute sulphuric acid is poured on a copper plate?

Answer 1

These are the two experiments to show the relative reactivity of metals.Iron nail is placed in copper sulphate solution to see which one is more reactive i.e. Iron or copper. During the reaction we find that the solution of copper sulphate gets decolourised. This indicates that iron being more reactive than copper, is able to displace copper from copper sulphate solution.Similarly when copper plate is dipped in dilute sulphuric acid solution, no reaction takes place. This is because copper is less reactive than hydrogen and thus it is not able to displace hydrogen gas from sulphuric acid.