Here's how to calculate the freezing point of the solution:

Understanding the Concepts

* Freezing Point Depression: The addition of a solute to a solvent lowers the freezing point of the solvent. This is a colligative property, meaning it depends on the amount of solute particles present, not their specific identity.

* Freezing Point Depression Equation:

ΔT_f = K_f * m * i

where:

* ΔT_f is the freezing point depression (change in freezing point)

* K_f is the freezing point depression constant for the solvent (water = 1.86 °C/m)

* m is the molality of the solution (moles of solute per kg of solvent)

* i is the van't Hoff factor (number of particles the solute dissociates into in solution)

Calculations

1. Calculate the molality (m):

* Moles of solute (NaI) = 0.550 moles

* Mass of solvent (water) = 615 g = 0.615 kg

* Molality (m) = moles of solute / kg of solvent = 0.550 moles / 0.615 kg = 0.895 m

2. Determine the van't Hoff factor (i):

* NaI dissociates into two ions in solution (Na⁺ and I⁻).

* Therefore, i = 2

3. Calculate the freezing point depression (ΔT_f):

* ΔT_f = K_f * m * i = 1.86 °C/m * 0.895 m * 2 = 3.34 °C

4. Calculate the new freezing point:

* The normal freezing point of water is 0 °C.

* New freezing point = 0 °C - 3.34 °C = -3.34 °C

Answer: The freezing point of the solution is -3.34 °C.