Which from following gases of same mass exerts highest pressure at constant temperature?

Let us consider the mass of each gas \(=1 \mathrm{~g}\) Order of molecular weight of the given gases: \(\mathrm{H}_2 \lt \mathrm{N}_2 \lt \mathrm{O}_2 \lt \mathrm{Cl}_2\)
\(\therefore \quad\) The order of no. of moles: \(\mathrm{H}_2\gt\mathrm{N}_2\gt\mathrm{O}_2\gt\mathrm{Cl}_2\)
From ideal gas equation, \(\mathrm{n} \propto \mathrm{V}\)
\(\therefore \quad\) Volume occupied by the gases is as follows:
\(\mathrm{H}_2\gt\mathrm{N}_2\gt\mathrm{O}_2\gt\mathrm{Cl}_2\)
At constant temperature, (Boyle's law)
\(P \propto \frac{1}{V}\)
Since volume occupied by \(\mathrm{Cl}_2\) gas is the least,
\(\therefore \quad \mathrm{Cl}_2\) gas exerts the highest pressure.