The molecular weight of a gas that diffuses twice as rapidly as a gas with molecular weight 64, is

Options

A. 6.4
B. 8
C. 128
D. 16

Answer

d

Explanation

`r_(1)=r, r_(2)=2r, M_(1)=64`
`r_(1)/r_(2)=sqrt(M_(2)/M_(1))`
`implies r/(2r)= sqrt(M_(2)/64)`
`r^(2)/(4r^(2))= M_(2)/64`
`therefore M_(2)= 16`