posted by arpit .
The volume at stp occuppied by a gas Q originally occupying 153.7dm at 287k and 750mm pressure (vapor pressure of gas Q at 287k is 12mm of Hg)
You may have asked a question but it isn't exactly clear. Do you want to calculate the volume at STP?
Use (P1V1/T1) = (P2V2/T2)