When the mass is the same, the number of molecules is inversely proportional to the molecular mass. This means less will be the molecular mass, more will be the number of molecules.
\(\mathrm{CO}_{2}=12 \times 2 \times 16=44 \mathrm{u}\)
\(\mathrm{N}_{2}=2 \times 14=28 \mathrm{u}\)
\(\mathrm{H}_{2}=2 \times 1=2 \mathrm{u}\)
\(\mathrm{CH}_{4}=12+4 \times 1=16 \mathrm{u}\)
Hence, \(1 \mathrm{~g} \mathrm{H}_{2}\) has maximum numbers of molecules.
