A gaseous mixture contain 50% He and 50% `CH_4` by volume. What is the percent by weight of `CH_4` in the mixture ?

Options

A. 0.1997
B. 0.2005
C. 0.5
D. 0.75

Answer

D

Explanation

`("vol. of He")/("vol. of " CH_4) = 50/50 = 1/1 `
` ("no. of molecules of He")/("no. of molecules of " CH_4) = 1/1`
`(" mass of He")/("mass of " CH_4) = 4/16 = 1/4`
% of `CH_4` in mixture ` = (4 xx 100)/(5) = 80.03%`