Agas diffuses 1/6 times faster than hydrogen gas (h2).

what is the molar mass of the gas?

= 72 g

Explanation:

According to the Graham's law of diffusion the rate of effusion or diffusion of a fixed mass of a gas is inversely proportional to the square root of its density or mass.For two gases; R1/R2 = √mm2/√mm1 ; where R1 and R2 are the rates of diffusion of the two gases  respectively, while mm1 and mm2 are the molecular masses respectively.

In this case; The other gas is heavier than hydrogen,

Therefore;  1/6 = √MM of H2 /√ MM of unknown gas

= 1/6 = √2/√x

= 1/36 = 2/x

x = 72

  = 72 g

Therefore; the molar mass of the other gas is 72 g