Boiling point $ \propto $ vander Waals force vander Waals force oc atomic mass (or molecular mass) $ \because $ Atomic mass of Xe is highest among. $ {{\text{H}}_{\text{2}}}\text{,He,}\,\text{C}{{\text{H}}_{\text{4}}}\text{,}\,\text{Xe} $ $ \therefore $ Boiling point of Xe is highest.