Describe with chemical equation the Laboratory method for the preparation of ammonia. Write its reaction with the following:
(i) Oxygen in presence of platinum at ${800}^{o}C$.
(ii) Red hot copper oxide.

Laboratory method for the preparation of ammonia:
Ammonium chloride is heated with calcium hydroxide.
$2N{H}_{4}Cl+Ca(OH{)}_2\stackrel{\Delta }{\to }CaC{l}_2+2N{H}_3+2H_{2}O$
Moist ammonia gas is dried over CaO (quik lime).
The reactions of ammonia with:
(i) Oxygen in presence of platinum at ${800}^{o}C$.
$4N{H}_3+5O_2\underset{{800}^{o}C}{\overset{Pt}{\to }}4NO+6H_{2}O$
(ii) Red hot copper oxide.
$2N{H}_3+3CuO\stackrel{\Delta }{\to }3Cu+3H_{2}O+N_2$