The higher boiling point of hydrogen fluoride is due to presence of strong hydrogen bonding between HF molecules which leads to association of HF molecules and requires higher energy for boiling. The boiling point of a given molecules depends upon the intermolecular interactions. Higher the strength of these interactions, higher is the value of boiling point of molecules. Down the group size of hydrogen halides increase so, van der waals' interaction increases. Order of boiling point is HF>HI>HBr>HCl