Question

A 2 molal solution of sodium chloride in water causes an elevation in the boiling point of water by 1.88 K. What is the value of Van’t Hoff factor? What does it signify? [Kb = 0.52 K kg mol^-1]

Answer 1

`Δ"T"_"b"("expected") = 0.52 xx 2 = 1.04`K

`Δ"T"_"b"("observed") = 1.88`

`"i" = (Δ"T"_"b"("observed"))/(Δ"T"_"b"("expected")) = 1.88/1.04 ≈ 2`

∴ NaCl dissoiates in two particles.