whats 'vapour density' of a gas????

Dear samidha

Vapour density is the density of a vapour in relation to that of hydrogen. It may be defined as mass of a certain volume of a substance divided by mass of same volume of hydrogen.

vapour density = mass of n molecules of gas / mass of n molecules of hydrogen

(By definition, the molar mass of a gas is the ratio of the mass of one molecule of gas to that of an hydrogen atom under similar conditions.)

Therefore:

vapour density = molar mass of gas / molar mass of H₂

vapour density = molar mass of gas / 2

vapour density = ½ × molar mass

(and thus: molar mass = 2 × vapour density)

Please feel free to post as many doubts on our discussion forum as you can.we will get you the answer and detailed  solution very  quickly.

All the best.

Regards,
Askiitians Experts
Prudhvi Teja

Now you can win exciting gifts by answering the questions on Discussion Forum. So help discuss any query on askiitians forum and become an Elite Expert League askiitian

Vapour density is a relative scale of measurement that tells us how many times a given gas is heavier than Hydrogen, when all measurements are made at identical conditions.

So, vapour density = Mass of the given gas / Mass of the same volume of H₂

As the Molecular weight of hydrogen is 2 amu,

V.D = Molecular Wt of the given gas / 2

2 x V.D = molecular wt of the given gas.