Colligative Properties

Question

To make something freeze at a higher temperature I would add more solvent?

Answer 1

Actually, adding more solvent to a solution will lower its freezing point and make it freeze at a lower temperature. This is because adding more solvent will decrease the concentration of the solute particles, which will reduce the number of particles available to form solid crystals and make it harder for the solution to freeze.

The phenomenon of lowering the freezing point of a solution is known as the freezing point depression, which is one of the colligative properties of solutions. The amount of freezing point depression is proportional to the concentration of the solute particles in the solution and is described by the equation:

ΔTf = Kf·m

where ΔTf is the freezing point depression, Kf is the freezing point depression constant (a characteristic property of the solvent), and m is the molality of the solution (moles of solute per kilogram of solvent).

Therefore, to make something freeze at a higher temperature, you would actually add more solute (not solvent) to the solution. This would increase the concentration of the solute particles in the solution and cause the freezing point depression to be less pronounced, resulting in a higher freezing temperature.