4. A pure liquid has a constant boiling point, but a liquid with a constant boiling point is not necessarily pure. Explain. 5. What effect does a reduction in the atmospheric pressure have on the boiling point of a liquid? 6. Why doesn't a pure liquid in a distilling flask vaporize all at once when the boiling temperature is reached 3 7. Why is it dangerous to heat a liquid in a distilling apparatus that is closed tightly at every joint and has no vent to the atmosphere? 8. Why is it important that the cooling water in a distillation apparatus enter the condenser jacket at the lower end and exit at the upper end, and not vice versa? 9. Why should a distilling flask be filled to not more than two-thirds of its capacity at the beginning of a distillation procedure?