COMEDK2022ChemistrySolutions
Which among the following forms minimum boiling azeotropes? (i) Heptane + Octane (ii) Water + Nitric acid (iii) Ethanol + Water (iv) Acetone + Carbon disulfide
Options
- A(i), (ii), (iv)
- B(i), (ii) only
- C(iii), (iv)
- D(iv) only
Correct answer
C. (iii), (iv)
Step-by-step solution
Minimum boiling azeotropes are formed by solutions showing large positive deviation from Raoult's law, where A-B interactions are weaker than A-A and B-B interactions. (i) Heptane + Octane: Both are similar non-polar alkanes, forming a nearly ideal solution. No azeotrope formed. (ii) Water + Nitric acid: Strong hydrogen bonding between unlike molecules causes large negative deviation from Raoult's law. Forms a maximum boiling azeotrope. (iii) Ethanol + Water: Mixing disrupts the extensive hydrogen bonding of pure w