Equal weights of ethane and hydrogen are mixed in an empty container at `25^(@)C`. The fraction of total pressure exerted by hydrogen is-

Options

A. `1:2`
B. `1:1`
C. `1:16`
D. `15:16`

Answer

D

Explanation

Let, `w_(C_(2)H_(6))=w_(H_(2))=w`
`n_(C_(2)H_(6))=(w)/(30) and n_(H_(2))=(w)/(2)`
`therefore x_(C_(2)H_(6))=(n_(C_(2)H_(6)))/(n_(C_(2)H_(6))+n_(H_(2)))=((1)/(30))/((1)/(30)+(1)/(2))=(1)/(16)`
[n=number of moles, x=mole-fraction]
similarly, `x_(H_(2))=(15)/(16)`
According to Dalton's law of partial pressure,
`p_(H_(2))=x_(H_(2))xxP` [P=total pressure]
or, `(P_(H_(2)))/(P)=x_(H_(2))=(15)/(16)`