Final answer:
The process by which the ammonia and hydrogen chloride gases move in the tube is called diffusion. the concentrated ammonia solution and concentrated hydrochloric acid are releasing their respective gases, and the gases are mixing and spreading out to create a more uniform concentration.
Step-by-step explanation:
The process by which the ammonia and hydrogen chloride gases move in the tube is called diffusion. Diffusion is the movement of particles from an area of high concentration to an area of low concentration.
In this case, the concentrated ammonia solution and concentrated hydrochloric acid are releasing their respective gases, and the gases are mixing and spreading out to create a more uniform concentration.