Ammonia, NH 3, is an alkaline gas and so turns damp red litmus paper blue. Ammonium ions (NH 4 +) – found in ammonium compounds such as ammonium chloride, ammonium nitrate and ammonium sulfate ...

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.