Calculate the freezing point of a solution containing 6.50g of benzene in 160g of chloroform

Freezing point of the solution will be -65.9°C

Explanation:

The addition of a solute to a solvent decreases freezing point of pure solvent. Freezing point depression formula is:

ΔT = K×m

Where ΔT is change in freezing point (-63.5°C is freezing point of pure chloroform), K is solvent constant (4.68°Ckg/mol for chloroform) and m is molality (moles of solute per kg of solvent).

Moles of benzene are:

6.50g × (1mol / 78.11g) = 0.0832 moles of benzene

0.0832 mol / 0.160kg = 0.52 mol/kg of solution.

Replacing these values in the formula:

(-63.5 - X)°C   = 4.68°Ckg/mol× 0.52 mol /kg

X = -65.9°C

Freezing point of the solution will be -65.9°C