Equal moles of hydrogen and oxygen gases are placed in a container with a pin-hole through which both can escape. What fraction of the oxygen excapes in the time required for one-half of the hydrogen to escape?
Considering the area of cross section to be the same, the velocity ratios can be replaces with volume ratios.
Since, volume∝number of moles for every mole of oxygen that is released, 4 moles of hydrogen is released.
Hence, if half the hydrogen escapes, 1/8th amount of the total oxygen escapes.