6.2 Hydrochloric acid produces a gas. So does ammonia solution. These two gases react when they meet to form a white solid called ammonium chloride.
Some cotton wool soaked in hydrochloric acid was placed at one end of a glass tube.
Some cotton wool soaked in ammonia solution was placed at the other end.
The diagram shows what happened.
cotton wool soaked
in hydrochloric acid
white band of ammonium chloride
formed when the gases meet
cotton wool soaked
in ammonia solution
I
a What is the name of the process by which the gases move along the tube?
bExplain how this process takes place.
The particles of hydrochloric acid have a greater mass than the particles
of ammonia. Suggest why the ammonium chloride is formed nearer to
the hydrochloric acid end of the tube than the ammonia solution end.