Question

50 ml of gas A diffuse through a membrane in the same time as 40 ml of a gas B under identical pressure-temperature conditions. If the molecular weight of A is 64, that of B would be

• A. 100
• B. 250
• C. 200
• D. 80

Answer 1

Answer: (A)

100

Answer 2

$\frac { r _ { 1 } } { r _ { 2 } } = \sqrt { \frac { M _ { 2 } } { M _ { 1 } } } \Rightarrow \frac { 50 / t } { 40 / t } = \sqrt { \frac { M _ { 2 } } { 64 } }$

$\frac { 50 } { 40 } = \sqrt { \frac { M _ { 2 } } { 64 } }$ or$\frac { 25 } { 16 } = \frac { M _ { 2 } } { 64 }$ or $M _ { 2 } = 100$