Question

If the density of air is $0.001293gm/cc$, then its vapour density at $STP$ is:

• A. 10
• B. 16
• C. 1.43
• D. 14.48

Answer 1

Answer: (D)

14.48

At STP (or) under standard conditions of pressure and temperature, $22.4L$ of any gas equals 1 mole.

The density of air is given as $0.001293g/ml$

The volume of gas= $22400ml$

Therefore, Mass= $0.001293\times 22400=28.96g$

we know that Molecular Mass= 2 x Vapour Density

Vapour Density= Molecular Mass ÷ 2

= $28.96÷2=14.48gm$

Hence, the correct option is $D$