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Quiz Chapter 5: Consumer and Industrial Chemistry

10 questions · Form 5 Chemistry Bab 3: Consumer and Industrial Chemistry

Question 1 of 10Score: 0

Why are detergents more effective than soaps when washing clothes in hard water?

Full Question List & Answer Key

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

1. Why are detergents more effective than soaps when washing clothes in hard water?

  1. Detergents produce more foam than soap in pure water
  2. Detergents do not form insoluble scum with calcium and magnesium ions
  3. Detergents are fully biodegradable compared to natural soaps
  4. Detergents contain no hydrophobic hydrocarbon chains
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Answer: B

Detergents form soluble calcium and magnesium salts in hard water, preventing the formation of insoluble scum.

2. Which component of food additives is added to improve the physical texture and viscosity of jelly or ice cream?

  1. Thickeners
  2. Antioxidants
  3. Preservatives
  4. Flavourings
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Answer: A

Thickeners like gelatin, agar-agar, and starch increase viscosity and give smooth texture to jellies and ice creams.

3. Why is it dangerous to stop taking a prescribed course of antibiotics prematurely?

  1. It leads to stomach ulceration
  2. It causes addiction to the medication
  3. Surviving bacteria may develop resistance to the antibiotic
  4. It destroys red blood cells
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Answer: C

Incomplete antibiotic courses allow surviving bacteria to mutate and develop antibiotic resistance, rendering future treatments ineffective.

4. Which part of a soap molecule dissolves in grease during cleansing action?

  1. Hydrophilic ionic head
  2. Hydrophobic hydrocarbon tail
  3. Sodium cation
  4. Glycerol backbone
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Answer: B

The non-polar hydrophobic hydrocarbon tail dissolves in grease, while the polar hydrophilic head stays in water.

5. Graphene is a 2D carbon allotrope. Which property makes graphene highly suitable for touchscreens and flexible electronics?

  1. High density and opacity
  2. High electrical conductivity, transparency, and mechanical flexibility
  3. High solubility in organic solvents
  4. Low thermal conductivity
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Answer: B

Graphene is transparent, flexible, extremely strong, and an excellent conductor of electricity, making it ideal for flexible displays.

6. Which traditional plant is commonly used to soothe skin burns and moisturise skin?

  1. Ginger
  2. Turmeric
  3. Aloe vera
  4. Tongkat Ali
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Answer: C

Aloe vera gel contains soothing compounds widely used for skin burns, sunburns, and moisturising.

7. What is the byproduct formed along with soap during saponification?

  1. Fatty acid
  2. Glycerol
  3. Ethanol
  4. Sulfonic acid
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Answer: B

Hydrolysis of triglycerides yields soap salts and glycerol (propane-1,2,3-triol).

8. Which food additive slows down the oxidation of fats and oils to prevent rancidity?

  1. Lecithin
  2. Tartrazine
  3. Ascorbic acid (Vitamin C)
  4. Monosodium glutamate
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Answer: C

Ascorbic acid (Vitamin C), BHA, and BHT are antioxidants that prevent fat oxidation and rancidity.

9. How does Green Technology address industrial air pollution caused by acidic gas emissions like SO₂?

  1. Using electrostatic precipitators to burn SO₂
  2. Using chemical scrubbers to neutralise acid gases before release
  3. Compressing acid gases into liquid fuel via pyrolysis
  4. Adding hydrogen gas to reduce SO₂ to elemental sulfur
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Answer: B

Industrial scrubbers spray alkaline solutions to neutralise acidic gases such as SO₂ and NO₂ before flue gases enter the atmosphere.

10. What reactants are required to produce soap through saponification?

  1. Fat or oil and concentrated alkali
  2. Fatty acid and alcohol
  3. Petroleum fraction and sulfuric acid
  4. Glycerol and dilute hydrochloric acid
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Answer: A

Saponification is the alkaline hydrolysis of fats or oils using concentrated alkalis like NaOH or KOH to produce soap and glycerol.

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