Which of the following gas molecules has the largest mean free path?

Options

A. `CO_(2)`
B. `H_(2)`
C. `O_(2)`
D. `N_(2)`

Explanation

Mean free path is the average distance travelled by a particle between two collisions
`lambda =(1)/(sqrt(2)pi sigma^(2)N)`
where `sigma` is collision, `N` is the number of molecules per unit volume.
So, `lambda` will be the highest for small value of `sigma`.
`H_(2)` will have small `sigma`.
Hence, the answer is (`b`).