MARTYN F. CHILLMAID / SCIENCE PHOTO LIBRARY MARTYN F. CHILLMAID / SCIENCE PHOTO LIBRARY
The ammonia test. There is no visible vapour from the ammonia in the test tube until a glass stirrer dipped in hydrochloric acid is put close by. As the vapours combine a visible smoke of ammonium hydroxide is formed. A droplet of hydrochloric acid has fallen into the tube and vaporised into a doughnut cloud.
Model release not required. Property release not required.