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Class 10 Chemistry Chapter 20 Water Test 8 | Punjab Board 2027
Grade 10 Chemistry Chapter 20 Water Test 8
Prepare for the Punjab Board Class 10 Chemistry Examination 2027 with Chapter 20: Water – Class Test No. 8. This full chapter test, including textbook exercises, is designed to help students prepare according to the new Chemistry syllabus issued by PECTAA Punjab. As part of the Punjab Board 2027 Model Papers and comprehensive Class 10 Chemistry Chapter-Wise Test Series, this test helps students revise important concepts, practice textbook exercise questions, assess their understanding, and improve their board examination preparation. Attempt this full chapter test to strengthen your Chemistry knowledge and prepare effectively for the 2027 annual examinations.
Full Chapter Test
T-8
CHAPTER # 20
Time:15 mint(Objective Type)Total Marks: 12
Note:Four possible answers A, B, C and D to each question are given. The choice which you think is correct, fill that circle in front of that question with Marker or Pen ink. Cutting or filling two or more circles will result in zero mark in that question.
1.
Water is essential for living organism to:
(a) colour to living organism(b) convert chemical reactions(c) Increase weight for body(d) To support Life
Answer: (d)
2.
At high altitudes, the boiling point of water is lower than 100°C due to:
(a) Increased impurities(b) Lower atmospheric pressure(c) Lower temperature of surroundings(d) Higher density of water
Answer: (b)
3.
Tap water may contain chlorine because:
(a) To increase pH(b) To make it safe during treatment(c) To remove calcium(d) To increase viscosity
Answer: (b)
4.
Eutrophication finally results in:
(a) Water purity(b) Fish growth(c) Oxygen depletion(d) Temperature rise
Answer: (c)
5.
Arsenic and cadmium increase the risk of:
(a) Diabetes(b) Heart attack(c) Cancer(d) Anemia
Answer: (c)
6.
Which impurity is removed by activated carbon?
(a) Sand Bacteria(b) Odour(c) Dissolved salts(d) Solid impurities
Answer: (b)
7.
To face the effects of climate change, we should take:
(a) No action(b) Appropriate measures(c) More flood irrigation(d) None of these
Answer: (b)
8.
Fertilizers helps plants mainly by:
(a) Increasing soil hardness(b) Improving soil color(c) Providing essential elements(d) Reducing soil moisture
Answer: (c)
9.
Biofertilizers improve soil:
(a) Color(b) Temperature(c) Health and structure(d) Smell
Answer: (c)
10.
The pH of distilled water is:
(a) 6.5(b) 8.5(c) 7(d) 7.5
Answer: (c)
11.
Which gases are dissolved in natural water from the atmosphere through diffusion?
(a) O2 and CO2(b) N2 and CO2(c) O2 and N2(d) O2, N2 and CO2
Answer: (d)
12.
The fertilizer harmful to paddy rice is:
(a) Super phosphate(b) Ammonium nitrate(c) Urea(d) Potassium sulphate
Answer: (b)
Here is Subjective Part of Paper.
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Marks: 48
CHEMISTRY (SUBJECTIVE TYPE)
Time: 1:45 minute
Part - I
2.Write short answers to any Five (5) questions:
[5x2=10](i)Why is the water test important in pharmaceutical industries?
Water used for making medicines must be free from harmful impurities and germs. Testing confirms its purity, so the medicines are safe and effective.
(ii)A sample of water boils at 102°C. Is it pure water?
No. Pure water boils at 100°C at normal pressure. A higher boiling point shows that salts or other impurities are dissolved in it.
(iii)Why does distilled water prevent corrosion?
Distilled water has no dissolved salts, minerals or ions. Without them it cannot conduct electricity easily or form deposits, so it does not rust or corrode metal parts.
(iv)Why is excess growth of algae harmful for aquatic life?
Excess algae block sunlight. When they die, bacteria decompose them and use up the dissolved oxygen, so fish and other aquatic animals die.
(v)Define eutrophication.
Eutrophication is the enrichment of water with nutrients (nitrates and phosphates from fertilizers and sewage). It causes excessive algae growth and finally loss of oxygen in the water.
(vi)What is 'Sludge' in a sedimentation tank?
Sludge is the soft, semi-solid mass of suspended particles that settles at the bottom of a sedimentation tank.
(vii)How does activated carbon (charcoal) remove organic compounds?
Activated carbon has a very large porous surface. Organic compounds (and odour, colour and chlorine) stick to this surface by adsorption and are removed from the water.
(viii)List any three steps to control the negative effects of water pollutants.
- Treat industrial and domestic wastewater before releasing it.
- Do not throw waste or chemicals into water bodies.
- Use fertilizers and pesticides in controlled amounts and spread awareness.
3.Write short answers to any Five (5) questions:
[5x2=10](i)How does the disposal of household chemicals in drains contribute to water pollution?
Detergents, bleach, paints and pesticides flow through drains into rivers and lakes. They add toxic substances and nutrients that harm aquatic life and make the water unsafe.
(ii)List any four factors responsible for water scarcity in Pakistan.
- Rapid growth in population.
- Low rainfall and climate change.
- Shortage of dams and reservoirs for storing water.
- Wastage and pollution of water.
(iii)What will happen if the current water management and rainfall situation in Pakistan continues?
The water shortage will become more severe. Drinking water, agriculture and industry will suffer, causing food shortage, disease and economic problems.
(iv)Differentiate between micro-nutrients and macro-nutrients.
Macro-nutrients are needed by plants in large amounts (N, P, K, Ca, Mg, S). Micro-nutrients are needed in very small amounts (Fe, Zn, Cu, Mn, B, Mo).
(v)Define fertilizers and state their importance.
Fertilizers are natural or synthetic substances added to soil to supply essential nutrients to plants. They replace the nutrients lost from the soil, improve plant growth and increase crop yield.
(vi)Why is ammonium nitrate not suitable for paddy rice?
Ammonium nitrate is very soluble. In flooded paddy fields its nitrate is washed away and lost as nitrogen gas by denitrification, so it is wasted and may pollute water.
(vii)For which crops are potassium fertilizers especially useful?
Potassium fertilizers are especially useful for potato, tomato, sugarcane, tobacco and fruit crops.
(viii)What are biofertilizers?
Biofertilizers are preparations of living micro-organisms (bacteria, algae, fungi) that add nutrients such as nitrogen to the soil and improve its fertility naturally.
4.Write short answers to any Five (5) questions:
[5x2=10](i)How to identify if water is polluted?
Polluted water often has a bad smell, unusual colour or taste, cloudiness and floating matter. Tests of pH, dissolved salts and germs confirm it.
(ii)How we conserve water at home?
Fix leaking taps, close taps when not in use, use a bucket instead of a hose, and reuse water for plants.
(iii)What is the main difference between tap water and distilled water?
Tap water contains dissolved salts, gases and some chlorine. Distilled water is pure and free from dissolved impurities.
(iv)Name useful and harmful substances present in water.
Useful: dissolved oxygen, calcium and magnesium salts. Harmful: arsenic, lead, cadmium, pesticides and germs.
(v)What is the difference between sedimentation and filtration?
Sedimentation: suspended particles settle down by gravity. Filtration: water is passed through filter material (sand, gravel) that traps the fine particles.
(vi)Why fertilizers containing nitrogen element are added into the soil?
Nitrogen is needed to make proteins and chlorophyll. Soil loses nitrogen through crops and washing away, so it is added to promote healthy green growth.
(vii)Why urea is regarded as a good nitrogenous fertilizer?
Urea has the highest nitrogen content (about 46%), is cheap, soluble in water and easy to store and apply.
(viii)Why Pakistan is facing a severe shortage of water?
Because of a growing population, low rainfall, climate change, few dams and reservoirs, wastage of water and water pollution.
Part - II
NOTE:- Attempt any two questions.[9x2=18]
5.
(a)How domestic water supply can be made fit for drinking?
- Sedimentation: let suspended particles settle.
- Coagulation: add alum so fine particles clump together.
- Filtration: pass water through sand and gravel beds.
- Disinfection: kill germs by chlorination or boiling.
- Aeration: improves taste and removes odour.
(b)Which measures should be taken to avoid water-borne disease?
- Boil or chlorinate drinking water.
- Keep water sources and storage tanks clean and covered.
- Dispose of sewage and waste properly.
- Wash hands with clean water and soap.
- Get vaccinated and follow health awareness programmes.
6.
(a)What are fertilizers? Mention the essential qualities of a good fertilizer.
Fertilizers are natural or synthetic substances added to the soil to supply essential nutrients to plants. Qualities of a good fertilizer:
- Soluble in water so plants can absorb it.
- Contains a good percentage of an essential nutrient.
- Not harmful to plants and soil.
- Cheap and easily available.
- Stable and easy to store and apply.
(b)What are the main functions of nitrogenous, phosphatic and potassium fertilizers?
- Nitrogenous: promote leaf and stem growth, make proteins and chlorophyll, give a dark green colour.
- Phosphatic: help root development, flowering, seed formation and early ripening.
- Potassium: increase disease resistance, activate enzymes and improve the quality of fruits and crops.
7.
(a)How can you avoid the negative effects of pollutants present in water?
- Treat industrial and domestic wastewater before discharge.
- Do not dump waste, oil or chemicals into rivers and lakes.
- Use fertilizers and pesticides in limited amounts.
- Use biodegradable detergents.
- Make and follow strict laws, and spread public awareness.
(b)Explain the reason of water scarcity in Pakistan. Also explain the steps to resolve these problem.
Reasons: rapid population growth, low rainfall and climate change, few dams and reservoirs, wastage of water, water pollution and old irrigation methods.
Steps:
Steps:
- Build more dams and reservoirs.
- Harvest rainwater.
- Line canals and use drip or sprinkler irrigation.
- Avoid wastage and recycle water.
- Control pollution and create public awareness.
