Answer:HF will have the highest boiling point
Explanation:
CH4 is non-polar hence contain only weak van der waals forces hence it will have a low boiling point. HCl will have a lower boiling point than HF since F is more electronegative than Cl and possess a greater degree of hydrogen bonding. P is much less electronegative than both Cl and F hence PH3 has a much less degree of hydrogen bonding. Hydrogen bonding exists between hydrogen and a weakly electronegative atom.
