How will you prepare heavy water from ordinary water? Explain its principle.

Explanation

Heavy water `(D_(2)O)` is prepared by prolonged electrolysis of ordinary water. As water is not a good conductor of electricity, an alkaline solution of water[-0.5(N) NaOH] is used for electrolysis. Bond dissociation energy of O-H bond is less than that of O-D bond . So, electrolysis of `H_(2)O` occurs at a faster rate and more easily than `D_(2)O`. Consequently, amount of `D_(2)O` in ordinary water increases. Pure `D_(2)`O is obtained when the amount of residual liquid decreases.