In which of the following there is intermolecular hydrogen bonding? — Chemical Bonding Chemistry Question

💡 Solution & Explanation

Step 1: Identify that ortho-fluorophenol (I) exhibits strong intramolecular hydrogen bonding, which significantly decreases its capacity to form intermolecular hydrogen bonds, thereby lowering its boiling point. Step 2: For ortho-chlorophenol (II) and ortho-bromophenol (III), intramolecular hydrogen bonding is weak or negligible due to the larger size of Cl and Br. Therefore, their boiling points are primarily governed by van der Waals forces, which increase with molecular size and weight (III > II). Step 3: Consequently, the boiling point order is III > II > I, which matches option (b).