Answer: 0.1 m BaCl 2.
- A 0.1 m BaCl<sub>2</sub>
- B 0.1 m NaCl
- C 0.1 m glucose
- D 0.1 m urea
Correct answer: A. 0.1 m BaCl<sub>2</sub>
Explanation: Boiling-point elevation is colligative and scales with the van't Hoff factor i. BaCl<sub>2</sub> gives 3 ions (i=3), the largest of the four, so it has the highest boiling point.
Adding a non-volatile solute lowers the solvent's vapour pressure at every temperature, which is the root cause behind all four colligative properties: it shifts the freezing point down and the boiling point up.
Concept context
Learn how substances dissolve and form mixtures. Covers concentration terms, colligative properties (boiling point elevation, freezing point depression, osmotic pressure), and ideal vs non-ideal solution behaviour.