Question

Vapour density of equilibrium mixture of NO2 and N2O4 is found to be 38.33 for the equilibrium. Find % dissociation for the reaction.
(1) 40.53
(2) 73.26
(3) 26.8
(4) 20

Answer 1

answer : option (4) 20

It has given that vapor density of equilibrium mixture of NO₂ and N₂O₄ is found to be 38.33 for the equilibrium.

we have to find the degree of dissociation.

dissociation of N₂O₄ into NO₂ is ....

N₂O₄ ⇔2NO₂

at t = 0 1

at eql 1 - α 2α

so, total number of moles at equilibrium, n_final = 1 - α + 2α = 1 + α

initial number of moles, n_initial = 1

using formula,

n_initial/n_final = M_experimental/M_theoritical

⇒1/(1 + α) = 76.66/92

[ M_experimental = 2 × vapor density, M_theoritical = molecular weight of N₂O₄ ]

⇒ (1 + α) = 92/76.66 = 1.20

⇒α = 0.2

therefore percentage degree of dissociation is 20%.