Question

A gases mixture contains oxygen and nitrogen in the ratio `1 : 4` by weight. Therefore, the ratio of the number of molecules is:
A. `1:4`
B. `7:32`
C. `1:8`
D. `3:16`

Answer 1

Correct Answer - B
`(n_(O_(2)))/(n_(N_(2))) = (((m_(O_(2))))/((M_(O_(2)))))/(((m_(N_(2))))/((M_(N_(2)))))`
where, `m_(O_(2)) =` given mass of `O_(2), m_(N_(2)) =` given mass of `N_(2)`, `M_(O_(2))=` molecular mass of `O_(2), M_(N_(2))=` molecular mass of `N_(2)`, `n_(O_(2))=` number of moles of `O_(2), n_(N_(2))=` number of moles of `N_(2)`
`= [(m_(O_(2)))/(m_(N_(2)))](28)/(32) = (1)/(4) xx (28)/(32) = (7)/(32)`