Question

Solid ammonium chloride undergoes sublimation on heating. In the vapour phase ammonium chloride decomposes to give NH₄(g) and HCI(g). The following equilibrium is established.

NH₄Cl(s) ⇌ NH₃(g)+ HCl (g)

What is the number of

i) phases in the system,

ii) components in the system, and

iii) degrees of freedom of the system?

Answer 1

(I) 2 phases, that is, solid and gaseous phases

(II) 3 components (NH4Cl, NH3 and HCl)

(III) The system is disordered because gases are given out during the sublimation. (Gases move randomly, hence the molecules are very free)