NEETChemistrySolutions
When two volatile liquids A and B are mixed, it is observed that the intermolecular attractive forces between A and B are stronger than those between A-A and B-B. Which of the following thermodynamic conditions applies to this mixing process at constant temperature and pressure?
Options
- A_ mix H > 0 and _ mix V > 0
- B_ mix H = 0 and _ mix V = 0
- C_ mix H < 0 and _ mix S < 0
- D_ mix H < 0 and _ mix V < 0
Correct answer
D. _ mix H < 0 and _ mix V < 0
Step-by-step solution
When the intermolecular attractive forces between A-B are stronger than the A-A and B-B interactions, the molecules are held more tightly together. This leads to a decrease in volume, so _ mix V Because stronger bonds are formed, energy is released, making the process exothermic, which means _ mix H Note that for the mixing of any two miscible liquids, the process is spontaneous and the entropy of the system always increases, so _ mix S > 0 . Answer: _ mix H < 0 and _ mix V < 0