Which of the following gases has minimum rms speed at a given temperature ?
The correct option is D Carbon dioxide.
By definition, we know that
where V is the molar volume which is a constant.
⇒vrms ∝ 1√M
Molar mass of oxygen is 32 g/mol
Molar mass of nitrogen is 28 g/mol
Molar mass of hydrogen is 2 g/mol
Molar mass of carbon dioxide is 44 g/mol
Since carbon dioxide has the highest molar mass, it has the least rms speed at a given temperature.
Hence, option (d) is the correct answer.