Question

Identify the type of equilibrium in the following physical processes:

a) Camphor(s) ⇌ Camphor(g)

b) Water ⇌ Ice

c) Carbon dioxide ⇌ Dry ice

d) Ammonium chloride(s) ⇌ Ammonium

Answer 1

• (a) Sublimation equilibrium
• (b) Freezing (melting) equilibrium
• (c) Sublimation equilibrium
• (d) Sublimation equilibrium

Answer 2

Solution:

• (a) Camphor(s) ⇌ Camphor(g): This is an equilibrium between a solid and its vapor – i.e. a sublimation–deposition equilibrium.
• (b) Water ⇌ Ice: This is the equilibrium between a liquid and its solid – the freezing–melting equilibrium.
• (c) Carbon dioxide ⇌ Dry ice: Here again, we have an equilibrium between a gas (CO₂) and its solid (dry ice), which is a sublimation–deposition equilibrium.
• (d) Ammonium chloride(s) ⇌ Ammonium: In this context, ammonium chloride sublimates (turns directly from solid to vapor) and then deposits back as a solid. Thus, this is also a sublimation–deposition equilibrium.

Minimal Explanation:

• (a), (c), and (d) involve phase change directly from solid to vapor (sublimation) and vice versa (deposition).
• (b) involves the phase change between liquid and solid (freezing/melting).