A perfectly ideal solution is rare but some solution behave nearly ideal. Which of the following does not fall in this category?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Ethanol and acetone
Nearly ideal solutions are formed when:
• Intermolecular forces between unlike molecules ≈ like molecules
• No hydrogen bonding or strong interactions
• Similar molecular size and nature
Option 1: n-hexane and n-heptane - Both are non-polar hydrocarbons. Similar structure and intermolecular forces. Behave nearly ideal.
Option 2: Ethanol and acetone Ethanol forms hydrogen bonding. Acetone can interact strongly with ethanol through hydrogen bonding. Unlike interactions differ significantly from pure liquids. Hence non-ideal solution.
Option 3: Benzene and toluene - Both are non-polar aromatic compounds. Similar molecular size and forces. Behave nearly ideal.
Option 4: Bromoethane and chloroethane - Similar polar molecules with comparable structure. Intermolecular forces are similar. Behave nearly ideal.