Each of the following pair shows a positive deviation from Raoult's law except — Solutions and Colligative Properties Chemistry Question

💡 Solution & Explanation

Diethyl ether (C2H5)2O and $HCl$ exhibit strong hydrogen bonding/intermolecular attractions between the ether oxygen and $HCl$. This increases solute-solvent interactions, resulting in a negative deviation from Raoult's law. The other pairs undergo disruption of existing cohesive forces (like hydrogen bonds in alcohols), causing positive deviations.