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?

1 Answer
Jul 23, 2016

In effect you are performing a gas diffusion experiment. It should be more rapid at elevated temperature.


#NH_3(g) + HCl(g) rarr NH_4Cl(s)darr#

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?