1 litre capacity flask containing `NH_(3)` at 1 atm and `25^(@)C` A spark is passed through until all the `NH_(3)` is decomposed into `N_(2)` and `H_(2)` Calculate the pressure of gases left at `25^(@)C` .

Options

A. 2 atm
B. 0.5 atm
C. 1.5 atm
D. 1 atm

Answer

A

Explanation

Ammonia decomposes into `N_(2)` and `H_(2)` completely when a spark is passed through it .
`NH_(3) (g) to (1)/(2)N_(2) (g) + (3)/(2)H_(2) (g)`
`{:("Initial pressure in atm." ,,) , (1 , o , " "o) , ("Final pressure " ,,) , (0 , (1)/(2) , " "(3)/(2)):}`
The total pressure of `N_(2)` and `H_(2)` after complete decomposition is given by
`P_(T) = P_(N_(2)) + P_(H_(2)) = 0.5 + 1.5` = 2 atm