Ammonia reacts with excess of chlorine to form :
Pure chlorine gas may react vigorously with ammonia gas. An excessive mix of the two gases in air can produce hazardous compounds such as nitrogen trichloride.
The following reaction takes place:
NH3+3Cl2⟶NCl3+3HCl
Ammonia reacts with excess of chlorine to form NCl3 and HCl.