1. 0.18 m MnBr2
2. 0.16 m BaCl2
3. 0.19 m ZnCl2
4. 0.51 m Ethylene glycol (nonelectrolyte)
A. Lowest freezing point
B. Second lowest freezing point
C. Third lowest freezing point
D. Highest freezing point
Can someone explain to me how can I solve this? I have been trying to do this but I still did not understand how to do this… I have more exercises like this one but I just want to understand how to do this…
Please HELP!!
Very Grateful,
1 Answer

The freezing points of the solutions are lowered by the number of particles in solution. Each of the three salts dissociate into three ions in solution, so you multiply their molalities by 3. The nonelectrolyte does not dissociate, so its molality stays the same. The freezing points can then be ranked according to the results you obtain above. The lowest freezing point comes from the solution with the highest molality times the van’t Hoff factor (3 for each salt, 1 for the ethylene glycol).
A – ZnCl2
B – MnBr2
C – Ethylene glycol
D – BaCl2