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Class 9 · Water Security · 10 Aug 2026

Max marks: 20
Grade Class 9 · Water Security · 11 questions
Name Class Date
Q.1 MCQ [3 marks]
(a)
Which municipal water treatment process involves adding chemicals like alum (aluminum sulfate) to clump together suspended colloidal impurities into heavier flocs?
[1 mark]
(a)  Sedimentation
(b)  Coagulation
(c)  Chlorination
(d)  Filtration
(b)
During water purification, why is aeration performed as one of the preliminary steps?
[2 marks]
(a)  To precipitate dissolved iron and manganese and remove volatile organic compounds causing bad tastes and odors
(b)  To add fluoride ions for dental health protection
(c)  To increase the temperature of water so bacteria multiply faster before chlorination
(d)  To filter out colloidal clay particles without the use of coagulants
Q.2 Match the Pairs [7 marks]
(a)
Match the water source classification in India to its correct characteristic description.
[2 marks]
Column AColumn B
1. Glacial Rivers a. Fed by melting snow and monsoon rains, ensuring year-round flow
2. Rainfed Tanks b. Artificial or natural reservoirs filled exclusively during the monsoon season
3. Confined Aquifers c. Water-bearing strata trapped between impermeable rock layers under pressure
Answer
(b)
Match each water source or term in Column A with its correct definition or classification in Column B.
[2 marks]
Column AColumn B
1. Inland Water Body a. Rivers and lakes forming part of surface water
2. Water Table b. The upper surface of the zone of saturation in groundwater
3. Desalination c. Process of removing dissolved salts from seawater
4. Rainwater Harvesting d. Collecting and storing precipitation for direct use
Answer
(c)
Match each stage of the municipal water supply journey with its primary engineering purpose.
[3 marks]
Column AColumn B
1. Intake Well a. Draws raw water from a river or reservoir
2. Alum Dosing Tank b. Coagulates fine suspended particles
3. Rapid Sand Filter c. Removes remaining fine impurities and bacteria flocs
4. Distribution Mains d. Transports potable water to residential neighborhoods
Answer
3.
The process of adding chlorine compounds to treated drinking water to destroy pathogenic microorganisms is known as _____.
[1 mark]
Q.4 One Sentence [2 marks]
(a)
State the primary function of a sluice valve in a municipal water pipeline network.
[1 mark]
(b)
State the primary function of overhead service reservoirs (water tanks) in an urban water supply network.
[1 mark]
Q.5 Short Answer [5 marks]
(a)
Define the term 'potable water' and state one reason why untreated river water in India is generally not considered potable.
[2 marks]
(b)
Explain why coagulants such as alum (aluminium sulphate) are added during the water treatment process before filtration.
[3 marks]
6.
Identify the four main sequential treatment stages in a standard municipal water treatment plant represented in the correct operational order.
[2 marks]
Label the following: 1 2 3 4
Generated by Lumai — 10 September 2026
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Class 9 · Water Security · 10 Aug 2026 — 20 Marks