10 questions · Form 5 Chemistry Bab 3: Consumer and Industrial Chemistry
Which additive acts as an emulsifier to keep oil and water mixed in mayonnaise?
Prefer reading to quizzing? All 10 questions are listed below with the answer and explanation under each one.
1. Which additive acts as an emulsifier to keep oil and water mixed in mayonnaise?
Answer: A
Lecithin (found in egg yolk) is an emulsifier that lowers surface tension to keep oil and water uniformly mixed.
2. Which food additive slows down the oxidation of fats and oils to prevent rancidity?
Answer: C
Ascorbic acid (Vitamin C), BHA, and BHT are antioxidants that prevent fat oxidation and rancidity.
3. Why are detergents more effective than soaps when washing clothes in hard water?
Answer: B
Detergents form soluble calcium and magnesium salts in hard water, preventing the formation of insoluble scum.
4. What prohibited chemical in illegal cosmetic products causes severe kidney and nervous system damage?
Answer: B
Mercury compounds in illegal skin-lightening creams cause toxicity leading to kidney damage and nervous system failure.
5. Which traditional plant is commonly used to soothe skin burns and moisturise skin?
Answer: C
Aloe vera gel contains soothing compounds widely used for skin burns, sunburns, and moisturising.
6. What is the byproduct formed along with soap during saponification?
Answer: B
Hydrolysis of triglycerides yields soap salts and glycerol (propane-1,2,3-triol).
7. Oils and fats are organic compounds belonging to which homologous series?
Answer: B
Oils and fats are triglycerides, which are tri-esters formed from glycerol and long-chain fatty acids.
8. Sodium benzoate is added to canned foods primarily as a:
Answer: B
Sodium benzoate is a chemical preservative that inhibits the growth of microorganisms (bacteria and fungi).
9. Why is it dangerous to stop taking a prescribed course of antibiotics prematurely?
Answer: C
Incomplete antibiotic courses allow surviving bacteria to mutate and develop antibiotic resistance, rendering future treatments ineffective.
10. Which reaction converts liquid vegetable oil into solid margarine in industry?
Answer: C
Hydrogenation adds hydrogen gas across C=C double bonds in unsaturated oils using a nickel catalyst at 180 °C to make solid margarine.