What is the freezing point of an aqueous solution that boils at 104 degree Celsius?

To determine the freezing point of an aqueous solution that boils at 104 degrees Celsius, we need to consider the concept of boiling point elevation and freezing point depression, which are colligative properties of solutions. These properties depend on the number of solute particles in a solvent, rather than the identity of the solute itself.

Understanding Boiling Point Elevation

In a pure water solution, the boiling point is 100 degrees Celsius at standard atmospheric pressure. When a solute is added, it disrupts the ability of water molecules to escape into the vapor phase, effectively raising the boiling point. In your case, since the solution boils at 104 degrees Celsius, we can infer that a solute has been added that raises the boiling point by 4 degrees Celsius.

Calculating Freezing Point Depression

Similarly, the presence of a solute lowers the freezing point of the solution. The extent of this freezing point depression can be calculated using the formula:

• ΔTf = i * Kf * m

Where:

• ΔTf = change in freezing point
• i = van 't Hoff factor (number of particles the solute dissociates into)
• Kf = freezing point depression constant for water (1.86 °C kg/mol)
• m = molality of the solution (moles of solute per kg of solvent)

Connecting Boiling Point Elevation to Freezing Point Depression

While we don't have the exact molality or the identity of the solute, we can still reason through the problem. The boiling point elevation of 4 degrees Celsius suggests that the solution is relatively concentrated. Typically, for many common solutes, the freezing point depression will be of a similar magnitude.

Estimating the Freezing Point

Given that the boiling point is elevated by 4 degrees Celsius, we can reasonably estimate that the freezing point might also be depressed by a similar amount. Pure water freezes at 0 degrees Celsius, so if we assume a freezing point depression of approximately 4 degrees Celsius, we can calculate:

• Freezing Point = 0 °C - 4 °C = -4 °C

This means that the freezing point of the aqueous solution is likely around -4 degrees Celsius. However, keep in mind that this is an estimation, and the actual freezing point could vary based on the specific solute and its concentration.

Final Thoughts

In summary, while we cannot pinpoint the exact freezing point without more specific information about the solute and its concentration, we can make a well-reasoned estimate based on the boiling point elevation. The freezing point of your aqueous solution that boils at 104 degrees Celsius is likely around -4 degrees Celsius, reflecting the colligative properties at play.