Question

At a fixed temperature, the vapour density of a gas with respect to nitrogen is greater than that of the gas with respect to hydrogen true and false.​

Answer 1

Answer:

The vapour density of a gas is half of its relative molecular mass.

Vapour density = Molar mass of gas / Molar mass of H2

Answer 2

given statement : At a fixed temperature, the vapour density of a gas with respect to nitrogen is greater than that of the gas with respect to hydrogen.

we have to check the above statement is true or false.

answer : false

explanation : vapor density of gas A with respect to gas B is given by , $V.D_{A,B}=\frac{V.D_A}{V.D_B}$ , where V.D denotes vapor density.

you should remember that the vapor density of any ideal gas is half of molecular mass of that gas.

so, vapor density of nitrogen gas = molecular mass of nitrogen gas/2 = 28/2 = 14

vapor density of hydrogen gas = molecular mass of hydrogen gas/2 = 2/2 = 1

case 1 : vapor density of a gas with respect to nitrogen = $\frac{V.D_{gas}}{14}$

case 2 : vapor density of the same gas with respect to hydrogen gas = $\frac{V.D_{gas}}{1}$

here it is clear that $\frac{V.D_{gas}}{14}$ < $V.D_{gas}$

hence, vapor density of a gas with respect to nitrogen gas is lesser than that of the gas with respect to hydrogen gas.

therefore it is false that the vapor density of a gas with respect to nitrogen is greater than that of the gas with respect to hydrogen.