50 mL of each gas A and of gas B takes 150 and 200 seconds respectively for effusing through a pin hole under the similar conditions. If molecular mass of gas A is 36, the molecular mass of gas B will be

Options

A. 96
B. 20.25
C. 32
D. 64

Answer

B

Explanation

`r_A/r_B = sqrt(M_B/M_A)`
`(V//t_A)/(V//t_B) = sqrt((36)/(M_A))`
`t_B/t_A =sqrt((36)/(M_A))`
`(36)/(M_A) = (200/150)^2`
`M_A = 20.25`