Equal volumes of two gases `A` and `B` diffuse through a porous pot in 20 and 10 seconds respectively if the molar mass of `A` be 80 find the molar mass of `B` .

Explanation

`:' (r_(A))/(r_(B))= sqrt((M_(B))/(M_(A)))`
`:. (V)/(20) xx (10)/(V) = sqrt((M_(B))/(80)) ( :' r = ("volume diffused")/(time))`
`:. M_(B) = (10 xx 10 xx 80)/(20 xx 20) =20 gmo1^(-1)` .