NEETChemistrySolutions
Two volatile liquids A and B are mixed to form a binary solution. If the intermolecular attractive forces between A and B are of exactly the same magnitude as the A-A and B-B intermolecular forces, which of the following statements is correct regarding the resulting solution?
Options
- AThe total vapour pressure of the solution is greater than that predicted by Raoult's law.
- BThe enthalpy of mixing ( _ mix H ) and volume of mixing ( _ mix V ) are both zero.
- CThe solution will form a minimum boiling azeotrope at a specific composition.
- DThe process of mixing the two liquids is accompanied by a decrease in entropy.
Correct answer
B. The enthalpy of mixing ( _ mix H ) and volume of mixing ( _ mix V ) are both zero.
Step-by-step solution
When the intermolecular attractive forces between the solute and solvent molecules ( A-B ) are of the same magnitude as those between the pure components ( A-A and B-B ), the solution formed is an ideal solution. For an ideal solution, the enthalpy of mixing ( _ mix H ) is zero because the energy required to break A-A and B-B interactions is exactly balanced by the energy released upon forming A-B interactions. Similarly, the volume of mixing ( _ mix V ) is zero because the molecules occupy the same volume in the m