Question

A gas that effuses through a porous cylinder 1.87 times faster than chlorine gas. what is the molar mass and identity.

Answer 1

From the Graham's law of effusion;
R1/R2 = √MM2/√MM1
Molar mass of chlorine gas is 71
Therefore;
1.87= √ 71 /√mm1
= 1.87² = 71/mm1 
mm1 = 71/1.87²
         = 71/3.4969
         = 20.3
Thus, the molar mass of the other gas is 20.3 , and i think the gas is neon