Consider the following compounds of comparable molar mass: (A) Propanoic acid (B) Butan-1-ol (C) Butanal (D) Pentane The correct decreasing order of their boiling points is:

Step-by-step solution

The boiling point of a compound depends on the strength of its intermolecular forces. All four compounds have comparable molar masses (ranging from 72 to 74 g/mol ). Propanoic acid (A) forms strong intermolecular hydrogen bonds and can exist as a cyclic dimer, leading to the highest boiling point. Butan-1-ol (B) also exhibits intermolecular hydrogen bonding, but it is less extensive and weaker than that in carboxylic acids. Butanal (C) possesses dipole-dipole interactions but lacks the ability to form intermolecula