A white ring of solid ammonium chloride forms where the two gases meet inside the tube. If necessary, protect non-glass surfaces of an overhead projector with clear plastic. Dip one Q-tip into ...

The equation shows that ammonium chloride (a white solid) can break down to form ammonia and hydrogen chloride. It also shows that ammonia and hydrogen chloride (colourless gases) can react to ...

Method: Dip a glass rod in concentrated hydrochloric acid and put this in a sample of the gas. Result: If ammonia is present, a white ‘smoke’ of ammonium chloride is observed.