The correct option is
C 14.48
Explanation:
We know that: Molecular Mass= 2x Vapour Density
At STP or under standard conditions of pressure and temperature, 22.4 l of any gas equals to 1 mole.
That is, 1 mole = 22.4 l
The density of air is given as 0.001293g/ml
The volume of gas=22400 ml
We know that mass= density x volume
Therefore, rearranging the above equation, Mass= 0.001293 x 22400= 28.96 g
Also we know that, Molecular Mass= 2 x Vapour Density
Rearranging the equation we get,
Vapour Density= Molecular Mass ÷ 2
=28.96÷2=14.48 gm
Option C is correct answer