The `N_(2)O_(4)//NO_(2(g))` equilibrium is endothermic as shown below:
`underset(Colourl es)(N_(2)O_(4(g)))hArrunderset(Dark brown)(2NO_(2(g)))`, (`DeltaH=+ve`)
The equilibrium is attained in a container having movable piston by taking `1 mol e` of `N_(2)O_(4(g))` at `50^(@)C` and `1 atm` pressure. At equilibrium, relative molecular mass of the mixture is `65.7`.
The degree of dissociation of `N_(2)O_(4)` at equilibrium is:

Options

A. `0.4`
B. `0.04`
C. `0.03`
D. `0.2`

Answer

A

Explanation

`underset(1-alpha)underset(1)(N_(2)O_(4(g)))hArrunderset(2alpha)underset(0)(2NO_(2(g)))`
`:. ("Normal mol.wt.")/("Exp.mol.wt.")=1-alpha+2alpha`
or `(92)/(65.7)=1+alpha`
`:. alpha=0.4`