what are ammonia and hydrochloric acid ?
Ammonia is gas made up of Nitrogen and Hydrogen (NH3) , it is basic in nature and thus reacts with acids. Hydrochloric acid is a compound of Chlorine and Hydrogen (HCl), it is highly corrosive in nature, and reacts with bases.
NH3(g) + HCl(g) → NH4Cl(s)