Which of the following relationships is correct,where $r$ is the rate of diffusion of a gas and $d$ is its density?

Gas $A$ diffuses $6$ times faster than hydrogen gas. What is the molar mass of $A$?

Explain the states of matter.

If two molecules of $A$ and $B$ have molar masses of $100 \ g/mol$ and $64 \ g/mol$ respectively,and the rate of diffusion of $A$ is $12 \times 10^{-3} \ mol/s$,then the rate of diffusion of $B$ will be:

Deep sea divers use a mixture of which gases for respiration?

Which of the following gases is not easily soluble in water?