Heavy water is left as a residue by carrying out the repeated electrolysis of ordinary water. Infact, its boiling point (374.42K) is slightly more than that of ordinary water (373K). It is very expensive and this can be judged by the fact about 29000 litres water on repeated electrolysis leave behind one litre of heavy water `(D_(2)O)`.
(i) How is heavy water different from ordinary water is its biological action?
(ii) Give the chemical reactions of heavy water with `Al_(4)C_(3) and CaC_(2))`.
(iii) What are the values associated with the use of heavy water?

Explanation

(i) Heavy water is injouries to human being, animals and plants since it slows down the rate of reaction that occurs in them. Ordinary water is no way injurious.
(ii) `Al_(4)C_(3)+12D_(2)P to 4Al(OD)_(3)+4Al(OD)_(3)+underset("Deuteromehtane")(CD_(4))`
`CaC_(2)+2D_(2)O toCa(OD)_(2)DC-=+underset("Deuteromehtane")(CD_(4))`