To find the boiling point of a solution made by mixing solid iodine with carbon tetrachloride, calculate the molality of the solution, use it with the ebullioscopic constant to find the boiling point elevation, and then add this to the solvent's normal boiling point.
The student is asking to calculate the boiling point of a solution made by mixing iodine with carbon tetrachloride. To solve this question, we need to use the boiling point elevation formula ΔT = i * Kb * m where ΔT is the boiling point elevation, i is the van 't Hoff factor (which is 1 for iodine, since it does not dissociate into ions), Kb is the ebullioscopic constant of the solvent (4.95 °C/m for carbon tetrachloride), and m is the molality of the solution.
Step 1: Calculate the molality (m) of the solution, which is moles of solute per kilogram of solvent. First, we need to find the moles of iodine (I2) by dividing its mass (55.87 g) by its molar mass (approximately 253.81 g/mol for I2). Then, we convert the volume of carbon tetrachloride (125 mL) to kilograms by using its density (1.584 g/cm3).
Step 2: Use the calculated molality with the Kb value to find the boiling point elevation (ΔT).
Step 3: Finally, add the boiling point elevation to the normal boiling point of carbon tetrachloride (76.8 °C) to find the boiling point of the mixture.