Add a few drops of 3M NH3 to each beaker. The solution will turn pink. Add a scoop of solid NH4Cl to one of the beakers. The pink color will become very faint or disappear. Use the other beaker as a ...

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 ...