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Quiz Chapter 5: Water and Solution

10 questions · Form 2 Science Bab 5: Water and Solution

Question 1 of 10Score: 0

What is the role of Slaked Lime (calcium hydroxide) in the municipal water treatment plant?

Full Question List & Answer Key

Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.

1. What is the role of Slaked Lime (calcium hydroxide) in the municipal water treatment plant?

  1. To neutralize acidic water and lower its acidity
  2. To kill harmful microorganisms
  3. To filter out large plant debris
  4. To add mineral taste to tap water
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Answer: A

Slaked lime is added during water treatment to adjust pH by neutralizing acidity caused by alum addition.

2. During the electrolysis of water, a gas collected at the cathode produces a 'pop' sound when tested with a burning wooden splint. What is this gas?

  1. Oxygen
  2. Hydrogen
  3. Nitrogen
  4. Carbon Monoxide
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Answer: B

Hydrogen gas collects at the cathode (negative pole) and reacts explosively with oxygen, causing a characteristic 'pop' sound.

3. Which water purification method produces pure distilled water free from suspended solids, microorganisms, and dissolved minerals?

  1. Filtration
  2. Chlorination
  3. Distillation
  4. Boiling
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Answer: C

Distillation involves evaporation followed by condensation, leaving behind all dissolved minerals and impurities.

4. What type of mixture is formed when chalk powder is shaken vigorously with water and left to stand?

  1. Dilute solution
  2. Saturated solution
  3. Suspension
  4. Colloid
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Answer: C

Chalk powder is insoluble in water, forming a suspension with visible floating particles that settle over time.

5. Which property allows water to travel upwards against gravity through narrow xylems in tall plants?

  1. High density at 4°C
  2. Capillary action (Cohesion and Adhesion)
  3. Electrolytic dissociation
  4. Low boiling point
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Answer: B

Capillary action, powered by cohesive forces between water molecules and adhesive forces against vessel walls, pulls water upward.

6. What is the primary purpose of adding Alum during the water purification treatment process?

  1. To kill pathogenic bacteria and viruses
  2. To cause fine suspended particles to clump together (coagulation)
  3. To reduce acidity and adjust water pH
  4. To prevent dental caries in the population
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Answer: B

Alum (aluminium sulphate) acts as a coagulant, causing small suspended mud and clay particles to form larger flocs.

7. Which factor decreases the rate of evaporation of water exposed in an open environment?

  1. Higher surrounding temperature
  2. Higher atmospheric humidity
  3. Faster wind speed
  4. Larger exposed surface area
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Answer: B

High air humidity means the air is already saturated with water vapor, slowing down the rate of evaporation.

8. Why does fine sugar dissolve faster in warm water than coarse sugar crystals in cold water?

  1. Fine sugar has a smaller total surface area and higher temperature slows down dissolution
  2. Higher temperature increases kinetic energy and smaller particle size increases total surface area
  3. Coarse sugar crystals react chemically with cold water to slow dissolution
  4. Warm water reduces the solubility limit of sugar
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Answer: B

Smaller particle size expands exposed surface area, while higher temperature increases particle kinetic energy and collision rate.

9. Which water treatment process kills bacteria but fails to remove suspended mud particles or dissolved salts?

  1. Distillation
  2. Boiling
  3. Filtration
  4. Sedimentation
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Answer: B

Boiling kills pathogenic bacteria through heat sterilization but leaves all physical solids and dissolved salts behind.

10. What is the volume ratio of Hydrogen to Oxygen gas produced during the electrolysis of pure water?

  1. 1 : 1
  2. 1 : 2
  3. 2 : 1
  4. 3 : 1
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Answer: C

Electrolysis splits water (H2O) into hydrogen and oxygen gases in a 2:1 volume ratio.

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