Question

The density of chlorine relative to air is:
A. $2.44$
B. $3$
C. found only experimentally
D. $4$

Answer 1

Vapor density is the density of a vapor in relation to that of hydrogen. It may be defined as the mass of a certain volume of a substance divided by mass of the same volume of hydrogen. The relative density is slightly different from the vapor density as the relative density is the density of any gas with respect to the density of any other random gas whereas the vapor density is the density of a gas with respect to only hydrogen gas.

Complete step by step answer:
As per the question, we have to determine the relative density of the chlorine with respect to the air. Relative density is a relative term and can be defined as the ratio of the molecular mass of one gas with respect to the molecular mass of another gas. This can be written mathematically as:
$R.D = \dfrac{{{M_{Cl}}}}{{{M_{air}}}}$
Where,$R.D =$Relative density
${M_{Cl}} =$ Molecular mass of chlorine = $2 \times 35.5 = 71$
${M_{air}} =$ Molecular mass of air = $29$ (experimentally determined)
Hence, substituting the values and on solving, we have:
$R.D = \dfrac{{71}}{{29}} = 2.44$

So, the correct answer is Option A.

Note:
The vapor density indicates whether a gas is denser (greater than one) or less dense (less than one) than air. The density has implications for container storage and personnel safety if a container can release a dense gas, its vapor could sink and, if flammable, collect until it is at a concentration sufficient for ignition. Even if not flammable, it could collect in the lower floor or level of a confined space and displace air, possibly presenting an asphyxiation hazard to individuals entering the lower part of that space.