Prepare for the Punjab Board Class 10 Chemistry Examination 2027 with Chapter 20: Water – Class Test No. 3. This full unit model paper is designed to help students revise important concepts and assess their understanding of the Water chapter according to the new Chemistry syllabus issued by PECTAA Punjab. As part of our Punjab Board 2027 Model Papers and Class 10 Chemistry Chapter-Wise Test Series, this practice test supports exam preparation, improves subject knowledge, and helps students build confidence for their annual board examinations. Explore our chapter-wise Chemistry tests for focused revision and effective preparation.
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Chapter: 20
Total Time: 35 min
CHAPTER WISE CLASS TEST
(Test # 3)Chemistry
Total Marks: 25
ABCD
1ABCD
2ABCD
3ABCD
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4ABCD
5ABCD
6ABCD
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7ABCD
8ABCD
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.
TIME: 10 MinOBJECTIVEMARKS: 8
Q.1:(08)
1.The pH of distilled water is:
(A) 6.5(B) 8.5(C) 7(D) 7.5
2.Anhydrous copper(II) sulphate is used to test for presence of:
(A) Acids(B) Bases(C) Water(D) Salts
3.The pH range of tap water is:
(A) 1-4(B) 4-6(C) 6.5-8.5(D) 9-14
4.The unpleasant odour in water can be removed by:
(A) adding chlorine(B) treating it with activated charcoal(C) sedimentation(D) filtration
5.What do fish and other aquatic organisms use dissolved oxygen for?
(A) To build shells(B) To breathe and survive(C) To dissolve minerals(D) To digest microplastics
6.Very small particles of plastics present in water are called:
(A) Nanoplastics(B) Microplastics(C) Macroplastics(D) Bioplastics
7.The source of harmful microbes in natural water:
(A) human and animal wastes(B) fertilizers used for crops(C) industrial waste-water(D) microbes in rocks
8.In sedimentation process, suspended particles settle at the bottom due to:
(A) Pressure(B) Temperature(C) Gravity(D) Magnetism
TIME: 25 MinSUBJECTIVEMARKS: 17
(PART – I)
Q.2 Write short answers to following questions.(6×2=12)
i.Name two methods to check the purity of water.
Ans: (1) Measure the boiling point (100 °C) and freezing point (0 °C) of the water. (2) Test its pH (pure water has pH 7) or test with anhydrous copper(II) sulphate for water.
ii.Explain the distillation of water.
Ans: Water is boiled to form steam, and the steam is cooled (condensed) back into liquid water. Dissolved salts and other non-volatile impurities stay behind, so the collected distillate is pure water.
iii.What is filteration?
Ans: Filtration is the separation of insoluble suspended solid particles from a liquid by passing the mixture through filter paper or a porous material. The solid remains as residue and the clear liquid passes through as filtrate.
iv.Write the effects of heavy metals in human.
Ans: Heavy metals such as lead, mercury, arsenic and cadmium accumulate in the body. They can damage the brain, kidneys, liver and nervous system, harm the development of children and may cause cancer.
v.How would you remove harmful bacteria and other microbes present in water?
Ans: By disinfection: boiling the water or adding chlorine (chlorination). Ozone or ultraviolet light can also kill harmful microbes.
vi.What is sedimentation?
Ans: Sedimentation is the settling of suspended solid particles at the bottom of a container due to gravity when water is left undisturbed. The clear water is then poured off.
(PART – II)
Note: Attempt the following question.
Q.3: What are the main functions of nitrogenous, phosphatic and potassium fertilizers?(5)
Ans:
• Nitrogenous fertilizers (e.g. urea): supply nitrogen for leaf and stem growth, give plants a green colour and increase protein content.
• Phosphatic fertilizers (e.g. superphosphate): promote root development, flowering, fruiting and seed formation.
• Potassium fertilizers (e.g. potassium chloride): improve resistance to disease and drought and improve the quality of fruits.
