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`.
The equilibrium pressure at which dissociation of `N_(2)O_(4)` will show degree of dissociation of `N_(2)O_(4)` to be `0.50` in the above case:

Options

A. `82.1 atm`
B. `65.7 atm`
C. `72.0 atm`
D. `70.0 atm`

Explanation

`{:(N_(2)O_(4),hArr,2NO_(2)),(1,,1),(0.5,,1+0.5xx2):}`
Moles at equilibrium `=2.5`
`:. P_(at eq.)=2.5xx0.0821xx400`
`=82.1 atm`