Which of the following best explains why distillation is effective for purifying water?

• A. Distillation removes impurities by filtering them out through a membrane.
• B. Distillation separates water from impurities based on differences in boiling points.
• C. Distillation works because water reacts chemically with impurities to form pure compounds.
• D. Distillation purifies water by adding chemicals that neutralize contaminants.

Answer: (B)

Verified step by step guidance

1. Understand the principle behind distillation: it is a separation technique that relies on differences in boiling points of substances in a mixture.
2. Recognize that when a mixture is heated, the component with the lower boiling point vaporizes first, leaving behind substances with higher boiling points.
3. In the case of purifying water, heating causes water to vaporize while many impurities, which have higher boiling points or are non-volatile, remain in the original container.
4. The water vapor is then condensed back into liquid form in a separate container, effectively separating it from the impurities.
5. Therefore, distillation is effective because it separates water from impurities based on their different boiling points, not by filtration, chemical reaction, or adding chemicals.