Which of the following option represent correct composition of a gaseous mixture containing `CH_(4(g)) & N_(2)O_(5(g))` & having vapour density equal to 19.5 ?

Options

A. Mass % of `CH_(4) =25 %`
B. Mole % of `CH_(4)=25 %`
C. Mass % of `CH_(4) =75%`
D. Mole % of `CH_(4)=75%`

Answer

D

Explanation

`M=2xxVD=39 gm`
`{:(CH_(4),"N_(2)O_(5)),(x,100-x):}`
`39=(xxx16+108(100-x))/100`
`3900=16x+10800-108 x`
`x=75`
Mass % `CH_(4)=(75xx16)/(75xx16+25xx108) xx100=30. 7%`