If a solution has a boiling-point elevation of 1.04 K, with Kb = 0.52 K kg mol⁻¹ and molality 1 m, what is the van’t Hoff factor i?

2

The boiling-point elevation equation is ΔTb = iKb m. Rearranging gives i = ΔTb/(Kb m). With the supplied values, i = 1.04/(0.52 × 1) = 1.04/0.52 = 2. A van’t Hoff factor greater than one indicates that the solute produces more effective particles than undissociated molecules, commonly because of dissociation. Thus, option C is correct.

This is a Class 11 Chemistry question. Chapter: Chemical Thermodynamics. Topic: Enthalpies of bond dissociation, combustion, atomization, sublimation, ionization, and solution.