How do you arrange these aqueous solutions in order of decreasing freezing point: 0.10 m Na3PO4, 0.35 m NaCl, 0.20 m MgCl2, 0.15 m C6H12O6, and CH3OOH?
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To arrange these aqueous solutions in order of decreasing freezing point, you need to consider the concept of colligative properties, specifically freezing point depression. The freezing point depression is the difference between the freezing point of a pure solvent and the freezing point of a solution.
The freezing point depression depends on the concentration of solute particles in the solution. The more solute particles present, the greater the freezing point depression.
To determine the number of solute particles, you need to consider the dissociation or association of the solute in solution. Ionic compounds like Na3PO4, NaCl, and MgCl2 dissociate into multiple ions, whereas molecular compounds like C6H12O6 (glucose) and CH3OOH (acetic acid) do not dissociate.
Let's analyze each of the solutions:
1. Na3PO4: Since Na3PO4 is an ionic compound, it dissociates into three Na+ ions and one PO4 3- ion in solution. Therefore, the total number of solute particles is 4.
2. NaCl: NaCl is also an ionic compound that dissociates into one Na+ ion and one Cl- ion in solution. Hence, the total number of solute particles is 2.
3. MgCl2: Like NaCl, MgCl2 is an ionic compound. It dissociates into one Mg2+ ion and two Cl- ions in solution. Hence, the total number of solute particles is 3.
4. C6H12O6 (glucose): Glucose is a molecular compound that does not dissociate into ions in solution. Therefore, the total number of solute particles is 1.
5. CH3OOH (acetic acid): Acetic acid is also a molecular compound that does not dissociate into ions. Hence, the total number of solute particles is 1.
Based on the number of solute particles, we can arrange these solutions in order of decreasing freezing point as follows:
Na3PO4 > MgCl2 > NaCl > C6H12O6 = CH3OOH
So, the solutions would be arranged in the following order of decreasing freezing point: 0.10 m Na3PO4 > 0.20 m MgCl2 > 0.35 m NaCl > 0.15 m C6H12O6 = CH3OOH.