Two aqueous solutions are prepared: 2.0 m Cu(NO₃)₂and 2.0 m NaBr. Which of the following statements is true? A)The Cu(NO ₃)₂solution has a higher vapor pressure and lower freezing point than the NaBr solution. B)The Cu(NO ₃)₂solution has a higher vapor pressure and higher freezing point than the NaBr solution. C)The Cu(NO ₃)₂solution has a lower vapor pressure and lower freezing point than the NaBr solution. D)The Cu(NO ₃)₂solution has a lower vapor pressure and higher freezing point than the NaBr solution. E)None of these choices are correct.

Question

Quizplus · Accepted Answer

The Cu(NO3)2 solution will dissociate into three ions (one Cu2+ and two NO3-) per formula unit, while NaBr will dissociate into two ions (one Na+ and one Br-) per formula unit. Solutions with a higher concentration of ions (or particles) have lower vapor pressure and lower freezing points due to colligative properties. Therefore, the Cu(NO3)2 solution, having more ions, will have a lower vapor pressure and a lower freezing point than the NaBr solution.

Two Aqueous Solutions Are Prepared: 2