1. Which method is commonly used at home to remove large suspended particles from water?
A) Distillation
B) Filtration
C) Chlorination
D) Fluoridation
Answer: B) Filtration
2. Boiling water mainly helps to:
A) Remove salts
B) Kill harmful microorganisms
C) Add minerals
D) Remove color
Answer: B) Kill harmful microorganisms
3. Which chemical is widely used in municipal water treatment plants for disinfection?
A) Oxygen
B) Nitrogen
C) Chlorine
D) Helium
Answer: C) Chlorine
4. The process of allowing heavy particles to settle at the bottom is called:
A) Sedimentation
B) Evaporation
C) Sublimation
D) Distillation
Answer: A) Sedimentation
5. Which purification method uses a semi-permeable membrane?
A) Boiling
B) Reverse Osmosis
C) Sedimentation
D) Screening
Answer: B) Reverse Osmosis
6. Reverse Osmosis (RO) systems are effective in removing:
A) Dissolved salts
B) Large stones
C) Leaves
D) Plastic waste
Answer: A) Dissolved salts
7. Activated carbon filters are mainly used to remove:
A) Microbes
B) Bad odor and taste
C) Sand
D) Heavy metals completely
Answer: B) Bad odor and taste
8. UV water purifiers work by:
A) Heating water
B) Filtering sand
C) Using ultraviolet radiation to kill germs
D) Adding chlorine
Answer: C) Using ultraviolet radiation to kill germs
9. Distillation purifies water by:
A) Chemical reaction
B) Freezing
C) Evaporation and condensation
D) Adding alum
Answer: C) Evaporation and condensation
10. Alum is added to water mainly for:
A) Disinfection
B) Coagulation
C) Sweetening
D) Coloring
Answer: B) Coagulation
11. The process of passing water through cloth to remove visible impurities is called:
A) Membrane separation
B) Simple filtration
C) Ion exchange
D) Chlorination
Answer: B) Simple filtration
12. Which method is most suitable during emergency situations without equipment?
A) Reverse Osmosis
B) UV Treatment
C) Boiling
D) Ionization
Answer: C) Boiling
13. Ion exchange method is commonly used to:
A) Remove hardness
B) Kill viruses
C) Remove plastic
D) Increase salinity
Answer: A) Remove hardness
14. Hard water mainly contains excess:
A) Sodium and Potassium
B) Calcium and Magnesium
C) Iron and Zinc
D) Nitrogen and Oxygen
Answer: B) Calcium and Magnesium
15. Which device is commonly used in homes in Pakistan for safe drinking water?
A) RO Plant
B) Steam Engine
C) Windmill
D) Solar Panel
Answer: A) RO Plant
16. Chlorination should be carefully controlled because excess chlorine:
A) Improves taste
B) Is harmless
C) Can cause bad taste and odor
D) Makes water sweet
Answer: C) Can cause bad taste and odor
17. Solar water disinfection (SODIS) uses:
A) Moonlight
B) Solar energy
C) Wind energy
D) Chemical tablets
Answer: B) Solar energy
18. Ceramic filters are mainly effective against:
A) Dissolved salts
B) Bacteria
C) Sugar
D) Oxygen
Answer: B) Bacteria
19. Which purification step usually comes first in water treatment plants?
A) Distribution
B) Sedimentation
C) Screening
D) Chlorination
Answer: C) Screening
20. Ozonation disinfects water using:
A) Hydrogen
B) Carbon dioxide
C) Ozone gas
D) Nitric acid
Answer: C) Ozone gas
21. Which household method does NOT remove dissolved salts?
A) RO
B) Distillation
C) Boiling
D) Ion Exchange
Answer: C) Boiling
22. Membrane filtration techniques include:
A) RO and Ultrafiltration
B) Boiling and Sedimentation
C) Screening and Decantation
D) Chlorination and Ozonation
Answer: A) RO and Ultrafiltration
23. Water purification tablets usually contain:
A) Sugar
B) Chlorine compounds
C) Sand
D) Copper
Answer: B) Chlorine compounds
24. Which process improves clarity by removing fine suspended particles?
A) Coagulation
B) Evaporation
C) Freezing
D) Sublimation
Answer: A) Coagulation
25. RO water may require remineralization because it:
A) Contains excess sugar
B) Removes useful minerals
C) Becomes colored
D) Smells bad
Answer: B) Removes useful minerals
26. Which is the safest storage method after purification?
A) Open bucket
B) Dirty container
C) Covered clean container
D) Rusted tank
Answer: C) Covered clean container
27. Fluoridation of water is mainly done to:
A) Kill bacteria
B) Improve digestion
C) Prevent tooth decay
D) Remove hardness
Answer: C) Prevent tooth decay
28. Which method is best for removing viruses effectively at home?
A) UV purifier
B) Cloth filtration
C) Sedimentation
D) Screening
Answer: A) UV purifier
29. Decantation is used after:
A) Distillation
B) Sedimentation
C) Ion exchange
D) Ozonation
Answer: B) Sedimentation
30. The main purpose of water purification is to make water:
A) Colored
B) Salty
C) Safe for drinking
D) Heavy
Answer: C) Safe for drinking