If the molal concentration in water is the same for the following substances, rank these solutions in decreasing melting point. Highest placed in the rank
will have the highest melting point
calcium phosphate, Ca3(PO4)2
glucose, C6H12O6
sodium chloride, NaCI
magnesium chloride, MgCl2
The ability of a solute to lower the freezing point of a solvent depends on the number of particles the solute breaks into in solution.
1. Sodium chloride, NaCl: NaCl breaks into two ions in solution (Na+ and Cl-), so it will have the highest melting point among the listed substances.
2. Magnesium chloride, MgCl2: MgCl2 breaks into three ions in solution (Mg2+ and 2Cl-), so it will have a lower melting point than NaCl but higher than the other substances.
3. Calcium phosphate, Ca3(PO4)2: Calcium phosphate will have a lower melting point than MgCl2 since it only breaks into two particles in solution.
4. Glucose, C6H12O6: Glucose does not break into ions in solution, so it will have the lowest melting point among the listed substances.