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Water & Its Management — Homi Bhabha Class 6 Chemistry MCQs with Solutions
Free Homi Bhabha Class 6 Chemistry Water & Its Management MCQs with step-by-step solutions covering The Water Cycle, Hard & Soft Water, Water Purification, Conservation & Rainwater Harvesting. Practise online on Prepizo — no login needed.
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Sample questions with solutions
Q1 — The Water Cycle · easy · theory
The changing of water into water vapour by the Sun’s heat is called …
A. Filtration
B. Condensation
C. Freezing
D. Evaporation ✓ Correct
Solution: When the Sun heats water in ponds, rivers and seas, the water slowly turns into an invisible gas called water vapour. This change is called evaporation.
Q2 — The Water Cycle · easy · theory
High in the sky, water vapour cools and forms tiny water droplets that make …
A. Wind
B. Clouds ✓ Correct
C. Soil
D. Rocks
Solution: As water vapour rises and cools, it turns into tiny droplets that gather together to form clouds.
Q3 — The Water Cycle · easy · theory
The falling of water from clouds as rain, snow or hail is called …
A. Melting
B. Boiling
C. Evaporation
D. Precipitation ✓ Correct
Solution: When the droplets in a cloud grow big and heavy, they fall to the ground as rain, snow or hail. This falling is called precipitation.
Q4 — The Water Cycle · easy · theory
Which of these gives the energy that keeps the water cycle going?
A. Light from the Moon
B. Sound from thunder
C. Cold from ice
D. Heat from the Sun ✓ Correct
Solution: The Sun’s heat evaporates water and starts the whole cycle, so the Sun is the main source of energy for the water cycle.
Q5 — Hard & Soft Water · easy · theory
Water that quickly makes a lot of lather (foam) with soap is called …
A. Salty water
B. Hard water
C. Soft water ✓ Correct
D. Muddy water
Solution: Soft water forms a rich lather easily with soap, so it is good for washing. Rainwater is a common example.
Q6 — Hard & Soft Water · easy · theory
Water that does NOT easily form lather with soap is called …
A. Hard water ✓ Correct
B. Distilled water
C. Rainwater
D. Soft water
Solution: Hard water does not lather well because the salts in it react with the soap instead of making foam. So it is called hard water.
Q7 — Hard & Soft Water · easy · theory
Which of these is usually an example of soft water?
A. Sea water
B. Water from a hot spring
C. Well water in a rocky area
D. Rainwater ✓ Correct
Solution: Rainwater has very few dissolved salts because it forms from evaporated water, so it is soft.
Q8 — Hard & Soft Water · easy · theory
The white, sticky, dirty solid formed when soap is used with hard water is called …
A. Foam
B. Cream
C. Scum ✓ Correct
D. Ice
Solution: In hard water the soap joins with the salts to form a white sticky solid called scum, instead of making lather.
Q9 — Water Purification · easy · theory
Boiling water before drinking makes it safe mainly because it …
A. Kills the germs in the water ✓ Correct
B. Makes the water sweeter
C. Adds salt to the water
D. Turns the water into ice
Solution: The heat of boiling kills the tiny germs (microbes) that cause diseases, so boiled water is safer to drink.
Q10 — Water Purification · easy · theory
Passing muddy water through a clean cloth to remove bits of dirt is an example of …
A. Freezing
B. Evaporation
C. Boiling
D. Filtration ✓ Correct
Solution: The cloth acts like a filter: the solid dirt stays on it while the water passes through. This is filtration.
Q11 — Water Purification · easy · theory
The tiny living things in dirty water that can make us ill are called …
A. Bubbles
B. Pebbles
C. Germs (microbes) ✓ Correct
D. Crystals
Solution: Very small living things called germs or microbes live in dirty water and can cause diseases, so water must be cleaned before drinking.
Q12 — Water Purification · easy · theory
Letting muddy water stand still so that the heavy mud settles at the bottom is called …
A. Sedimentation ✓ Correct
B. Lathering
C. Boiling
D. Chlorination
Solution: When muddy water is left undisturbed, the heavier dirt slowly sinks to the bottom. This settling is called sedimentation.
Q13 — Conservation & Rainwater Harvesting · easy · theory
Collecting rainwater from rooftops and storing it for later use is called …
A. Filtration
B. Water pollution
C. Rainwater harvesting ✓ Correct
D. Evaporation
Solution: Catching the rain that falls on roofs and saving it in tanks or letting it soak into the ground is called rainwater harvesting.
Q14 — Conservation & Rainwater Harvesting · easy · theory
Which habit saves water while you brush your teeth?
A. Using two taps at once
B. Turning off the tap while brushing ✓ Correct
C. Brushing under a shower
D. Leaving the tap running the whole time
Solution: Keeping the tap off while brushing and only opening it when needed saves many litres of water each day.
Q15 — Conservation & Rainwater Harvesting · easy · theory
What should you do with a tap that keeps dripping?
A. Leave it dripping, it is only a little
B. Open it fully so it stops
C. Cover it with a cloth
D. Repair it quickly to stop the waste ✓ Correct
Solution: Even a slow drip wastes a lot of water over time, so a leaking tap should be repaired as soon as possible.
Q16 — Conservation & Rainwater Harvesting · easy · theory
Watering plants slowly, drop by drop, right near their roots is called …
A. Rain harvesting
B. Drip irrigation ✓ Correct
C. Flood irrigation
D. Sprinkling from far
Solution: Drip irrigation gives water drop by drop directly to the roots, so very little water is wasted.
Q17 — The Water Cycle · hard · theory
Why does the water on Earth almost never run out even though we keep using it?
A. New water is made in the clouds every day
B. Water is brought from the Sun as rain
C. The same water is used again and again through the water cycle ✓ Correct
D. Plants make fresh water from soil
Solution: Water is not created or destroyed in the cycle. The same water keeps moving between the ground, the air and the clouds, so it is used over and over again.
Q18 — The Water Cycle · hard · theory
Sea water is salty, yet rainwater is not salty. Why?
A. The Sun turns the salt into water
B. The clouds add sugar to the water
C. Rain washes the salt away in the sky
D. When sea water evaporates, the salt is left behind and only pure vapour rises ✓ Correct
Solution: Only the water turns into vapour during evaporation; the salt stays behind in the sea. So the vapour, and the rain formed from it, is fresh and not salty.
Q19 — Hard & Soft Water · hard · theory
Why does soap not clean clothes well in hard water?
A. Hard water makes the soap too slippery
B. Hard water turns the soap into oil
C. The soap reacts with the salts to form scum instead of making lather ✓ Correct
D. The soap dissolves completely and disappears
Solution: The calcium and magnesium salts in hard water react with the soap to make a useless scum. Little soap is left to form lather, so cleaning is poor.
Q20 — Hard & Soft Water · hard · theory
Rainwater is soft when it falls, but the water in some wells is hard. How does the water become hard?
A. It gets heated by the Sun underground
B. It dissolves calcium and magnesium salts as it flows through rocks and soil ✓ Correct
C. It freezes and melts many times
D. It mixes with soap in the ground
Solution: As soft rainwater soaks through the ground, it slowly dissolves calcium and magnesium salts from the rocks, and this makes the water hard.
Q21 — Water Purification · hard · theory
Which of these CANNOT be removed from water by simple filtration?
A. Salt that is dissolved in the water ✓ Correct
B. Sand floating in the water
C. Tea leaves
D. Small pieces of leaf
Solution: Dissolved salt spreads out among the water and passes right through a filter, so filtration cannot remove it. Filtration only removes solid bits that do not dissolve.
Q22 — Water Purification · hard · theory
To get completely pure water from sea water, the water is boiled and the steam is cooled back into liquid. This method is called …
A. Distillation ✓ Correct
B. Sedimentation
C. Sieving
D. Chlorination
Solution: In distillation the water is boiled to steam and then condensed back to liquid. The salts and germs are left behind, so the collected water is very pure.
Q23 — Conservation & Rainwater Harvesting · hard · theory
How does rainwater harvesting help a village during a dry summer with no rain?
A. It stops water from ever evaporating
B. It turns sea water into fresh water
C. The rainwater stored or soaked into the ground can be used when there is no rain ✓ Correct
D. It makes the Sun produce more rain in summer
Solution: Rainwater collected during the rainy season is stored or added to the groundwater. This saved water can then be used later when rain is not falling.
Q24 — Conservation & Rainwater Harvesting · hard · numerical
A rooftop harvesting system collects about 100 litres of rainwater each time it rains. How much is collected after 6 rains?
A. 6000 litres
B. 600 litres ✓ Correct
C. 106 litres
D. 60 litres
Solution: Multiply the amount per rain by the number of rains: 100 × 6 = 600 litres.
Q25 — The Water Cycle · medium · theory
The process in which water vapour changes back into liquid water is called …
A. Evaporation
B. Transpiration
C. Condensation ✓ Correct
D. Precipitation
Solution: When water vapour cools down, it turns back into liquid water droplets. This change from gas to liquid is called condensation.
Q26 — The Water Cycle · medium · theory
Water given out into the air from the leaves of plants is called …
A. Germination
B. Filtration
C. Transpiration ✓ Correct
D. Respiration
Solution: Plants take up water from the soil and release some of it as vapour through their leaves. This is called transpiration and it adds water vapour to the air.
Q27 — The Water Cycle · medium · theory
Which is the correct order of steps in the water cycle?
A. Evaporation → Condensation → Precipitation → Collection ✓ Correct
B. Precipitation → Collection → Condensation → Evaporation
C. Condensation → Evaporation → Collection → Precipitation
D. Collection → Precipitation → Evaporation → Condensation
Solution: First water evaporates, then the vapour condenses into clouds, then it falls as precipitation, and finally the water collects in seas and rivers to begin again.
Q28 — The Water Cycle · medium · numerical
The Sun evaporates about 6 litres of water from a small pond each day. How much water evaporates in 5 days?
A. 25 litres
B. 36 litres
C. 11 litres
D. 30 litres ✓ Correct
Solution: Multiply the daily amount by the number of days: 6 × 5 = 30 litres.
Q29 — Hard & Soft Water · medium · theory
Hard water is hard mainly because it contains dissolved salts of …
A. Iron and gold
B. Sugar and salt
C. Calcium and magnesium ✓ Correct
D. Sand and clay
Solution: The hardness of water is caused by dissolved calcium and magnesium salts that it picks up from rocks and soil.
Q30 — Hard & Soft Water · medium · theory
A simple way to make hard water softer at home is to …
A. Shake it well
B. Add more soap to it
C. Boil it ✓ Correct
D. Cool it in a fridge
Solution: Boiling hard water makes some of the dissolved salts separate out and settle, which reduces the hardness of the water.