Two adiabatic cylinders are divided internally into two equal parts by a semi-permeable membrane. The membrane only lets hydrogen pass through it. The first cylinder has one half filled with hydrogen (P=1atm) and other half is vacuum initially. The second cylinder has the first part filled with hydrogen(P=1atm) and the second part with oxygen (P=2atm) initially.
When both systems achieve equilibrium, what is the ratio of hydrogen gas (moles) present on either sides of the partition in both cases.
I can see that the first cylinder will have hydrogen in ratio 1:1, but I have a problem with the second part. I think there shouldn't be any diffusion because the pressure on the other side is already greater. But as it turns out, the answer given for second part is also 1:1. Can someone tell me why this is so?