1. Question 1 of 25

   The purpose of chlorination is to:

   A Add minerals B Remove hardness C Remove colour only D Kill disease-causing germs
2. Question 2 of 25

   After adding a chlorine tablet to water in a household container, one should wait about ___ before drinking.

   A 30 minutes B 5 minutes C 10 hours D 1 minute
3. Question 3 of 25

   Which toxic element contaminates groundwater in parts of Punjab and Sindh?

   A Arsenic B Iron C Potassium D Calcium
4. Question 4 of 25

   The process of letting heavy suspended particles settle at the bottom is called:

   A Aeration B Evaporation C Condensation D Sedimentation
5. Question 5 of 25

   Domestic ceramic candle filters mainly remove:

   A Dissolved gases B Dissolved salts C Suspended particles and some bacteria D Hardness completely
6. Question 6 of 25

   A sand filter mainly removes:

   A Dissolved gases B Suspended particles C Dissolved salts D Hardness ions
7. Question 7 of 25

   Which disease spreads mainly through contaminated water and food?

   A Measles B Dengue C Malaria D Hepatitis A
8. Question 8 of 25

   RO plants are commonly used to remove ___ from brackish water.

   A Only sand B Oxygen C Nitrogen D Dissolved salts
9. Question 9 of 25

   Which method gives the purest water, free of dissolved salts?

   A Filtration B Chlorination C Distillation D Alum treatment
10. Question 10 of 25

    Alum is used in water treatment as a:

    A Disinfectant B Oxidising agent C Coagulant D Softener
11. Question 11 of 25

    To make water safe by boiling, it should be brought to a rolling boil for at least:

    A 1 minute B 10 seconds C 30 seconds D 5 seconds
12. Question 12 of 25

    The acceptable pH range for drinking water is about:

    A 4.0 to 5.0 B 9 to 12 C 1 to 4 D 6.5 to 8.5
13. Question 13 of 25

    Temporary hardness of water is caused by:

    A Chlorides and sulphates of calcium and magnesium B Sodium chloride C Bicarbonates of calcium and magnesium D Sodium nitrate
14. Question 14 of 25

    Which gas is commonly used to disinfect municipal drinking water?

    A Hydrogen B Helium C Chlorine D Nitrogen
15. Question 15 of 25

    In solar disinfection (SODIS), clear plastic bottles are exposed to bright sunlight for about:

    A 6 hours B 3 days C 10 minutes D 30 minutes
16. Question 16 of 25

    Which of the following is a water-borne disease?

    A Cholera B Malaria C Dengue D Tuberculosis
17. Question 17 of 25

    According to Pakistan's national drinking water standards, the maximum permissible total dissolved solids (TDS) is:

    A 300 mg/L B 1000 mg/L C 2000 mg/L D 100 mg/L
18. Question 18 of 25

    Ultraviolet (UV) purifiers disinfect water by:

    A Adding chlorine B Removing dissolved salts C Softening the water D Damaging the DNA of microbes
19. Question 19 of 25

    Cholera is caused by a bacterium called:

    A Vibrio cholerae B Hepatitis A virus C Plasmodium D Salmonella typhi
20. Question 20 of 25

    Activated charcoal in water filters removes bad taste and odour by:

    A Neutralisation B Adsorption C Distillation D Evaporation
21. Question 21 of 25

    Which chemical is commonly used to remove permanent hardness?

    A Alum B Washing soda (sodium carbonate) C Chlorine D Common salt
22. Question 22 of 25

    Which Pakistani organisation conducts research and monitors drinking water quality?

    A Pakistan Railways B Pakistan Council of Research in Water Resources (PCRWR) C Pakistan State Oil D SUPARCO
23. Question 23 of 25

    Spraying water into the air to remove dissolved gases and odour is called:

    A Distillation B Aeration C Coagulation D Sedimentation
24. Question 24 of 25

    In reverse osmosis, water is forced through a semi-permeable membrane by applying:

    A Light B Vacuum C Pressure D Heat
25. Question 25 of 25

    Which method removes temporary hardness of water?

    A Chlorination B Filtration C Sedimentation D Boiling

You can practise as a guest, but sign in to save your score and track your progress.