When a bottle of conc. ammonia is opened next to an open bottle of conc. hydrochloric acid, a fine white residue forms in mid-air BETWEEN the open bottles. How do we rationalize this observation?
In effect you are performing a gas diffusion experiment. It should be more rapid at elevated temperature.
Both ammonia and hydrogen chloride are gaseous. Certainly when you open a bottle of conc. ammonia you get the pungent smell of ammonia; don't do this with conc. acid. The ammonia should diffuse more quickly than the acid (it has half the molecular mass), but where the gases meet there will be a chemical reaction, as indicated by a fine white solid of what product?