For which of the following reactions average molar mass at any progress of reaction can not be 60 gm/mole.

Options

A. `SO_(3) (g) rarr SO_(2) (g) + (1)/(2) O_(2) (g)`
B. `N_(2)O_(4) (g) rarr 2NO_(2) (g)`
C. `Cl_(2) (g) rarr 2Cl (g)`
D. `2 NH_(3) (g) rarr N_(2) (g) + 3H_(2) (g)`

Answer

D

Explanation

`{:(2NH_(3) (g),rarr,N_(2) (g),+,3H_(2) (g),),(1,,0,,0,),(1 - 2x,,x,,3x,):}`
`M_(avg) = ((1 - 2x) 17 + x (28) + 3x xx 2)/(1 + 2x) = 60`
`17 = 60 + 120 x`
x will be -ve which is not possible