Volume of different gas in a container I know that technically two or more gases in one container should have different volumes. But when you imagine the gas molecules being mixed together, it look sorta like the two gases have the exact same volume, that is the volume of the container.

Also, in one of the questions I did on gas laws, wet hydrogen and hydrogen are shown to have the same volume in a container. Given the barometric pressure, I subs tract the vapor pressure at the certain temperature from it. Then I sub the pressure of dry hydrogen gas into the ideal gas law along with the volume of the container to find the number of mole of hydrogen gas.


This is the part in my textbook that I am confused about. It shows how partial pressure fraction is equal to the corresponding mole fraction. But this is all under the assumption that the volume and other things are constant. I am lost right here, because Avogadro's theory states the volume and mole number of a gas are directly proportional. 
( wait...wouldn't this mean that pressure, mole and volume are all directly proportional to one another???)

Can anyone give a answer, along with a proof/ a source?
Your second idea, that they have the same volume, is correct.  Each gas in a mixture of gases stored in the same container has the volume of that container.  Remember that gases are mostly empty space, so it is not a problem that their volumes overlap.

As is implied by your comment about subtracting the vapor pressure of water from the pressure of wet hydrogen, the gases in a mixture can have different partial pressures. Perhaps that is your point of confusion.  

The only case where they would have different volumes would be in a more accurate gas model than ideal gases, something like the Van der Waals model, where gas volume is corrected by a small amount to account for the portion of space that is taken up by the gas particles.

In short, each component of a mixture of gases stored in a given container shares the same volume and temperature and may (or may not) have different partial pressures and number of moles.