Question

If the 3.90 m solution from Part A boils at 103.45 ∘C, what is the actual value of the van't Hoff factor, i? The boiling point of pure water is 100.00 ∘C and Kb is equal to 0.512 ∘C/m.

Answer 1

Some of the solutions exhibit colligative properties. These properties depend on the amount of solute dissolved in a solvent. For boiling point elevation, we calculate the increase in temperature by the equation:

ΔT(boiling point) = (Kb)mi

where Kb is a constant, m is the molality of the solution, i is the van't Hoff factor.

From the given data, we can easily calculate for i as follows:

ΔT(boiling point) = (Kb)mi
103.45 - 100 = (0.512)3.90i
i = 1.73 <-------van't Hoff factor