2 Which parameter indicates the amount of salts dissolved in water? A pH B Hardness C TDS D Turbidity
3 Which method is used to kill harmful microorganisms in water? A Filtration B Chlorination C Sedimentation D Aeration
4 Water pollution can be reduced by: A Dumping waste in rivers B Treating sewage before disposal C Using more pesticides D Deforestation
5 Permanent hardness of water is caused by: A Bicarbonates B Chlorides and sulphates of calcium and magnesium C Carbonates D Hydroxides
6 Soft water is suitable for: A Drinking only B Washing and cleaning C Industrial cooling only D Agriculture only
7 Eutrophication results in: A Increase in oxygen level B Death of aquatic life C Clear water D Better drinking water
13 Which of the following is a safe drinking water indicator? A High turbidity B Neutral pH C High hardness D Presence of bacteria
15 Which activity increases water pollution? A Water treatment B Industrial waste discharge C Recycling D Rainfall
17 Hardness of water is mainly due to the presence of: A Sodium salts B Calcium and magnesium salts C Potassium salts D Iron salts
18 Which indicator shows the acidity or alkalinity of water? A Turbidity B pH C Hardness D Temperature
19 Which property of water helps in temperature regulation? A Low density B High specific heat C Low boiling point D High volatility
20 Which practice helps prevent water-borne diseases? A Using polluted water B Drinking untreated water C Boiling drinking water D Storing water openly
23 Which of the following is a chemical water pollutant? A Plastic waste B Oil spills C Bacteria D Algae
24 Clean water is essential mainly for: A Industries only B Agriculture only C Human health and environment D Animals only
25 Which of the following is a physical pollutant of water? A Bacteria B Suspended solids C Detergents D Pesticides
27 Which method is used to remove temporary hardness? A Adding washing soda B Boiling C Ion exchange D Distillation
28 Which process uses resin to soften water? A Boiling B Ion exchange process C Chlorination D Sedimentation
30 Which household method improves drinking water quality? A Mixing chemicals B Boiling C Adding sugar D Shaking