Vapour density of a compound is defined as the ratio of mass of a certain volume of gas to the mass of the same volume of hydrogen gas under conditions of temperature and pressure.
Vapour density`=("Mass of certain of gas"(22.4L)"at STP")/("Mass of same volume of" H_(2) "gas"(22.4L)"at STP")`
`=(Mw)/(2)`
i.e., Molecular mass of gas=Vapour density `xx2`
Vapour density is a unitless quantity it is unaffected by variation of temperature and pressure.
At STP, 5.6 litre of a gas weighs 60g. the vapour density of gas is:

Options

A. 60
B. 120
C. 30
D. 240

Answer

B