Question

Choose the correct order of density:

• A. $Hydrogen<Methane<Helium<Oxygen$
• B. $Hydrogen<Helium<Oxygen<methane$
• C. $Hydrogen<Methane<Oxygen<Helium$
• D. $Hydrogen<Helium<Methane<Oxygen$

Answer 1

The correct option is D $Hydrogen<Helium<Methane<Oxygen$

Density is mass over volume. If we keep every gas in a unit volume container their density will be equal to their masses.For unit moles of gases their masses will be equal to their molecular weights.So density will be equal to their molecular weights.

Molecular weight of:

$H=1$

$He=2$

$C{H}_4=16$

$O_2=32$

Order of density:$Hydrogen<Helium<Methane<Oxygen$