A gaseous mixture contains oxygen and nitrogen in the ratio `1 : 4` by weight. Therefore, the ratio of the number of molecules is:

Options

A. `1:4`
B. `7:32`
C. `1:8`
D. `3:16`

Answer

B

Explanation

The number of moles is given by `n= ("weight (w)")/("molecular weight (M)")`
Thus, ratio of moles of `O_(2) "an " N_(2)` is given by
`(n_(O_(2)))/(n_(N_(2)))= ((W_(O_(2))//M_(O_(2)))/(W_(N_(2))//M_(N_(2))))= ((W_(O_(2)))/(W_(N_(2)))) ((M_(N_(2)))/(M_(O_(2))))`
`=((1)/(4))xx ((28)/(32))= (7)/(32)`
Hence, ratio of `n_(O_(2)) and n_(N_(2))` is 7:32