Answer: ebullioscopic constant.
- A cryoscopic constant
- B ebullioscopic constant
- C universal gas constant
- D rate constant
Correct answer: B. ebullioscopic constant
Explanation: Kb is the ebullioscopic (molal boiling-point-elevation) constant of the solvent.
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.