Two gases A and B having the same volume diffuse through a porous partition in 20 and 10 seconds respectively. The molecular mass of A is 49u. Molecular mass of B will be `:`

Options

A. 50.00u
B. 12.25u
C. 6.50u
D. 25.00u

Answer

B

Explanation

`(r_(A))/( r_(B)) = sqrt(( M_(B))/( M_(A)))`
`( V//20)/( V//10) = sqrt((M_(B))/( 49))`
`(1)/(2) = sqrt((M_(B))/(49)) :. M_( B) = 49 xx (1)/( 4) = 12.25 `