What happens when hydrogen reacts with (i)`O_(2)`(ii) `Cl_(2)` (ii) Na ?

Explanation

(i) `2H_(2(g))+O_(2(g))to2H_(2)O_((l))` - Water
(ii) `H_(2(g))+Cl_(2(g))to2HCI_((g))` - Hydrogen Chloride
(iii) `2Na_((s))+H_(2(g))toNaH_((s))`- Sodium hydride