Why is glycerol purified by distillation under reduced pressure?

1. A Option A: Reduced pressure increases its vapour pressure permanently
2. B Option B: It decomposes at its normal boiling point, and lower pressure lowers the boiling point
3. C Option C: Its vapours are poisonous at normal pressure
4. D Option D: It boils too quickly at normal pressure

Answer checked 11 October 2026 · How we write and check questions