Chlorine is passed into (i) excess aqueous ammonia and (ii) ammonia in the presence of excess chlorine. The main nitrogen-containing products are, respectively,

1. A(i) $\mathrm{NCl}{}_3$ and $\mathrm{HCl}$; (ii) $\mathrm{N}{}_2$ and $\mathrm{NH}{}_4\mathrm{Cl}$
2. B(i) $\mathrm{N}{}_2\mathrm{H}{}_4$ and $\mathrm{HCl}$; (ii) $\mathrm{NCl}{}_3$ and $\mathrm{HCl}$
3. C(i) $\mathrm{N}{}_2$ and $\mathrm{NH}{}_4\mathrm{Cl}$; (ii) $\mathrm{NCl}{}_3$ and $\mathrm{HCl}$
4. D(i) $\mathrm{N}{}_2$ and $\mathrm{NH}{}_4\mathrm{Cl}$; (ii) $\mathrm{NO}$ and $\mathrm{HCl}$