Question

300cm³ of hydrogen diffuses through a porous pot in 50 seconds how long will it take 500 cm cube of oxygen diffuses through the same pot(h=1,o=16)​

Answer 1

It takes 333.3 s for Oxygen to diffuses

Further explanation  

Graham's law: the rate of effusion of a gas is inversely proportional to the square root of its molar masses or  

the effusion rates of two gases = the square root of the inverse of their molar masses:  

$\rm \dfrac{r_1}{r_2}=\sqrt{\dfrac{M_2}{M_1} }$

or  

$\rm M_1\times r_1^2=M_2\times r_2^2$

r₁ H₂ = 300 cm³/50 s=6 cm³/s

M₁ H₂ = 2 g/mol

M₂ O₂ = 32 g/mol

$\tt 2\times 6^2=32\times r_2^2\\\\r_2^2=\dfrac{2\times 6^2}{32}=2.25\rightarrow r_2=1.5$

the diffusion time of Oxygen :

$\tt r_2=\dfrac{V}{t}\\\\t=\dfrac{V}{r_2}=\dfrac{500~cm^3}{1.5~cm^3/s}=333.3~s$