Equal masses of methane and oxygen are mixed in an empty container at `25^(@)C`. The fraction of the total pressure exerted by oxygen is:

Options

A. `(1)/(3)xx(273)/(298)`
B. `(1)/(3)`
C. `(1)/(2)`
D. `(2)/(3)`

Answer

B

Explanation

Let the mass of methane and oxygen be x g each.
`"Moles of "CH_(4)=(x)/(16)`
`"Moles of "O_(2)=(x)/(32)`
`"Total moles "=(x)/(16)+(x)/(32)=(3x)/(32)`
`p_(O_(2))=p_("total")xx x_(O_(2))`
`(p_(O_(2)))/(p_("total"))=x_(O_(2))=((x)/(32))/((3x)/(32))=(1)/(3)`