Question

Mixture A is formed using KCl and H2O and mixture B is formed using MgCl2 and H2O. If the two mixtures have the same molality, which of the following statements would be true about the boiling point of the mixtures?

A. Mixture A would have a higher boiling point
B. Mixture A would have a lower boiling point
C. Mixture B would have a lower boiling point
D. The mixtures have the same boiling point
E. The mixtures would vaporize at the same rate

Answer 1

Considering the van't Hoff factor in boiling point elevation, mixture B (MgCl2 and H2O) would have a higher boiling point than mixture A (KCl and H2O) because MgCl2 dissociates into more ions.

Step-by-step explanation:

When comparing the boiling points of mixture A (KCl and H2O) and mixture B (MgCl2 and H2O) with the same molality, we must consider the van't Hoff factor (i), which accounts for the number of particles the solute dissociates into in solution. KCl dissociates into two ions (K+ and Cl-), whereas MgCl2 dissociates into three ions (Mg2+ and 2Cl-). Since MgCl2 produces more particles, it will have a greater effect on boiling point elevation. Hence, mixture B (MgCl2 and H2O) would have a higher boiling point than mixture A (KCl and H2O). Therefore, the correct answer is B. Mixture A would have a lower boiling point.