Match the LIST-I with LIST-II.
| LIST-I Binary solution | LIST-II Type of solution |
| A. n-Hexane and n-Heptane | I. Isotonic with fluid inside blood cell |
| B. Nitric acid and Water | II. Minimum boiling azeotrope |
| C. 0.9 % sodium chloride solution | III. Ideal solution |
| D. Ethanol and Water | IV. Maximum boiling azeotrope |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → A-III, B-IV, C-I, D-II
Binary liquid mixtures are classified by how the A–B interactions compare with the A–A and B–B interactions:
Ideal solution: A–B interactions are nearly the same as A–A and B–B; the solution obeys Raoult’s law, with ΔmixH = 0 and ΔmixV = 0.
Positive deviation: A–B interactions are weaker; the vapour pressure is higher than expected. A large positive deviation gives a minimum boiling azeotrope.
Negative deviation: A–B interactions are stronger; the vapour pressure is lower than expected. A large negative deviation gives a maximum boiling azeotrope.
An azeotrope boils at a constant temperature with the same composition in liquid and vapour, so it cannot be separated by fractional distillation.
A. n-Hexane and n-Heptane — This matches III. Ideal solution. Both are non-polar alkanes of similar size, so the intermolecular forces in the mixture are the same as in the pure liquids.
B. Nitric acid and Water — This matches IV. Maximum boiling azeotrope. Strong hydrogen bonding between \( \ce{HNO3} \) and water gives a negative deviation; the azeotrope (about 68% \( \ce{HNO3} \)) boils at about 393.5 K.
C. 0.9 % sodium chloride solution — This matches I. Isotonic with fluid inside blood cell. Normal saline has the same osmotic pressure as the cell fluid, so blood cells neither swell nor shrink in it.
D. Ethanol and Water — This matches II. Minimum boiling azeotrope. Ethanol breaks some of the hydrogen bonds of water, giving a positive deviation; the azeotrope (about 95% ethanol by volume) boils at about 351 K.
Shortcut: The pair B–IV appears only in Option (4).