A tube with on inside dianeter of $1cm$ and length $20cm$ is filled

with air and hydrogen $(H_2)$ at a total pressure of $1$ atm and

temperature of $273K.$ If the portial pressure of air is $0,75$atm

at one and of the tube and $0,25$ atm at the other end, find the

rate of diffusion for the following case;

a$)$ Steady$-$state equimolor counter diffusion

b$)."$ counter diffusion where