How to Determine the Freezing Point of an Unknown Solution

If you have an unknown solution that you want to identify, explore physical properties of this solution. One of the most significant physical properties is the freezing point. The freezing point is defined as the temperature at which the liquid and solid phases of a solution exist in a state of equilibrium. Therefore, when the solution begins to solidify, the freezing point has been obtained. A very simple procedure will allow you to determine the freezing point of an unknown solution--and in turn be able to discover more about the solution.

Things You'll Need

• Beaker
• Cold water
• Ice cubes
• Solution
• Test tube
• Thermometer

Instructions

1. Fill the beaker about halfway with cold water and ice cubes. This will help you to freeze the solution more efficiently.

2. Pour the solution into a test tube. Fill the test tube slightly above the halfway mark.

3. Place the test tube into the beaker with the cold water and the ice cubes. Then, place the thermometer inside the test tube. This will enable you to record the temperature at which the unknown solution begins to freeze.

4. Watch the unknown solution closely, keeping an eye out for crystal formation. When the crystals begin to form within the unknown solution, record the temperature. This temperature will function as the freezing point of the unknown solution.

References

• Bodner Research Web: Melting Point and Freezing Point