Comment on the reactions of dihydrogen with (a) chlorine, (b) sodium and (c) copper (II) oxide.

Explanation

(i) Dihydrogen reduces chlorine into chloride `(Cl ^(-))` ion and itself gets oxidised to `H^(+)` ion by chlorine to form hydrogen chloride. An electron pair is shared between H and Cl leading to the formation of a covalent molecule. (ii) Dihydrogen is reduced by sodium to form NaH. An electron is transferred from Na to H leading to the formation of an ionic compound, `Na^(+)H^(-)`. (iii) Dihydrogen reduces copper(II) oxide to copper in zero oxidation state and itself gets oxidised to `H__(2)O`, which is a covalent molecule.