How to purify water by boiling - Exam
  • 1. What is the primary purpose of boiling water for purification?
A) To remove sediment
B) To add minerals
C) To improve the taste
D) To kill harmful microorganisms
  • 2. At what temperature does water typically need to boil to be purified?
A) 100°C (212°F)
B) 75°C (167°F)
C) 50°C (122°F)
D) 150°C (302°F)
  • 3. How long should water be boiled to ensure effective purification?
A) 5 minutes
B) 30 seconds
C) 15 seconds
D) 1 minute
  • 4. In mountainous areas, should the boiling time be increased or decreased?
A) Increased
B) Decreased
C) Stay the same
D) Depends on humidity
  • 5. Why is longer boiling time required at higher altitudes?
A) Water boils at a lower temperature
B) Water boils at a higher temperature
C) The air is less dense
D) The water is purer
  • 6. What type of container is best for boiling water?
A) Stainless steel
B) Cardboard
C) Plastic
D) Aluminum
  • 7. What should you do before boiling water for purification?
A) Add sugar
B) Add salt
C) Filter out sediment
D) Chill the water
  • 8. Does boiling water remove chemical contaminants?
A) No
B) Yes, most of them
C) Yes, all of them
D) Yes, only chlorine
  • 9. What should you do after boiling the water?
A) Add lemon
B) Add ice
C) Drink it immediately
D) Let it cool down
  • 10. What organisms are effectively killed by boiling?
A) Bacteria and viruses
B) Pesticides
C) Heavy metals
D) Microplastics
  • 11. Can boiling water remove taste or odor issues?
A) No, never
B) Only bad odors
C) Sometimes
D) Yes, always
  • 12. What is the best way to store boiled water?
A) In the refrigerator uncovered
B) In an open container
C) In direct sunlight
D) In a clean, sealed container
  • 13. For how long is boiled water generally considered safe to drink?
A) 1 month
B) 24 hours
C) 1 week
D) Indefinitely
  • 14. What fuel source is suitable for boiling water?
A) All of the above
B) Only gas
C) Only electricity
D) Only wood
  • 15. How does water look when it's boiling?
A) Still and clear
B) Bubbling vigorously
C) Frothy on top
D) Steaming gently
  • 16. If you only have slightly cloudy water, is boiling enough?
A) Boiling is better after filtering
B) Cloudiness is irrelevant
C) Yes, boiling makes it safe
D) No, it's not safe
  • 17. What if the water source is suspected to be heavily contaminated with chemicals?
A) Just boil it longer
B) Boiling will remove all contaminants
C) Boiling is not sufficient
D) Boil it twice
  • 18. What does "purification" mean in the context of water?
A) Making it colder
B) Changing the color
C) Adding flavors
D) Removing harmful substances
  • 19. Does boiling soften hard water?
A) No, never
B) Partially
C) Yes, completely
D) Makes it harder
  • 20. Can you use a microwave to boil water for purification?
A) Yes, but it may not be as effective
B) No, never
C) Only if it has a special setting
D) Yes, it's the best method
  • 21. Why might microwave boiling be less effective?
A) It's more energy-efficient
B) Faster boiling
C) Uneven heating
D) Higher temperature
  • 22. What is the relationship between water hardness and boiling?
A) Hardness prevents boiling.
B) Boiling increases hardness.
C) Boiling reduces some hardness.
D) Boiling has no effect on hardness.
  • 23. What is the first step when purifying water from an unknown source?
A) Add chlorine.
B) Locate the water source.
C) Boil the water.
D) Filter the water.
  • 24. What is the most reliable method of making water safe to drink?
A) Filtering alone
B) Boiling alone
C) Multiple methods
D) Adding iodine.
  • 25. Which of the following is NOT removed by boiling water?
A) Bacteria
B) Viruses
C) Lead
D) Protozoa
  • 26. What is the purpose of letting boiled water cool before drinking?
A) Prevent burns
B) Improve the taste
C) Add oxygen
D) Increase purity
  • 27. What does vigorously boiling water mean?
A) Gentle simmer
B) Completely evaporated
C) Rolling boil
D) Just starting to steam
  • 28. Which of the following will help remove particulate matter from water before boiling?
A) Exposing the water to sunlight
B) Filtering the water
C) Adding sugar to the water
D) Freezing the water
  • 29. Why should you consider the source of the water?
A) Source doesn't matter
B) Because all sources are equally safe
C) To assess likely contaminants
D) Because all water tastes the same
  • 30. What's a portable water boiling device?
A) Camping stove
B) Swimming pool
C) Garden hose
D) Shower head
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