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

Options

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

Answer

B

Explanation

`(r_(A))/(r_(B))=sqrt((M_(B))/(M_(A))) or, (V//20)/(V//10)=sqrt((M_(B))/(49)) or, (1)/(2)=sqrt((M_(B))/(49))`
`therefore M_(B)=12.25u`.