The reaction of dimerisation of `NO_(2)` in `N_(2)O_(4)` is `2NO_(2)hArrN_(2)O_(4)`. The reaction is carried out by taking `1` mole each of `NO_(2)` and `N_(2)O_(4)` in a closed vessel of `1` litre at `400 K`. The equilibrium pressure was found to be `77 atm`.
Addition of one mole of an inert gas to the above equilibrium shows that degree of dissociation and equilibrium pressure of `N_(2)O_(4)` is

Options

A. `prop` decrease, `P=77 atm`
B. `prop` increase, `P=77 atm`
C. `prop` does not change, `P=110.0 atm`
D. `prop` decreases, `P=110.0 atm`

Explanation

The dissociation of `N_(2)O_(4)` remains unaffected since addition of inert gas at constant volume does not change `'alpha'`
Also `P=3.35xx0.0821xx400=110 atm`