Correct Answer - 2
`2NH_(3) rarr N_(2)+3H_(2)`
At same `P` and `T`
Number of moles after reaction `(n_(2))`
`=2xx` unmber of moles before reaction `(n_(1))`
`:. P propn`
`:. (P_(1))/(P_(2)) = (n_(1))/(n_(2)) = (1)/(2)`
Pressure after reaction `=2atm` .