Answer to Question #342209 in General Chemistry for Zenie

Question

Arrange the following according to increasing freezing point:

1m NaCl, 1m CaCl2, 1m C6H12O6, 1m AlCl3

Explain your answer.

Answer 1

The freezing point depends on the number of particles in the solution. The higher the number of particles, the lower the freezing point.

All are 1M solutions, so the numbers depend on ionization in solution:

NaCl → Na⁺ , Cl^– (2 particles)

CaCl₂ → Ca²⁺, Cl^– , Cl^– (3 particles)

C₆H₁₂O₆ (no ionization, so 1 particle)

AlCl₃ → Al³⁺ , Cl^– , Cl^– , Cl^– (4 particles)

Therefore, arrangement according to increasing freezing point: AlCl₃ < CaCl₂ < NaCl < C₆H₁₂O₆ .