Question

When a sample of NO₂ is placed in a container, the equilibrium is established rapidly.

2NO₂(g) ⇋  N₂O₄(g)

Equilibrium mixture is darken in colour at high temperature and low pressure. This indicates that

(a) ΔH is +ve and NO₂ is darken in colour than N₂O₄

(b) ΔH is +ve and N₂O₄ is darken in colour than NO₂

(c) ΔH is -ve and NO₂ is darken in colour than N₂O₄

(d) ΔH is -ve and N₂O₄ is darken in colour than NO₂

Answer 1

Correct Option (c) ΔH is -ve and NO₂ is darken in colour than N₂O₄

Explanation:

In this process low pressure favours backward reaction because the number of moles of reactants are greater than that of product and high temperature favours backward reaction only when the process is exothermic i.e., ΔH = -ve