Ten original SPM-style multiple-choice questions with answers and reasons, plus three structured questions with model answers, covering every content standard of the Form 5 Consumer and Industrial Chemistry chapter, all original, none copied from past-year papers.
Attempt each question before reading the answer. The multiple-choice section trains recall and quick reasoning; the structured section trains the fuller explanations, especially the cleaning action of soap and property-to-use answers. Every question here is original, written in SPM style on the same content standards, never a copied past-year paper.
Paper 1 style: multiple-choice
Q1. Which statement about oils and fats is correct? A. Fats are unsaturated and liquid at room temperature B. Oils are saturated and solid at room temperature C. Oils contain carbon-to-carbon double bonds D. Fats decolourise bromine water quickly
Answer: C. Oils are unsaturated, so they contain C=C double bonds; fats are saturated and usually solid.
Q2. Why does an unsaturated oil have a lower melting point than a saturated fat? A. Its molecules are heavier B. Its double bonds kink the chains so molecules pack less closely C. It contains more oxygen atoms D. It is made from animals
Answer: B. The kinks from C=C bonds weaken the forces between molecules, lowering the melting point.
Q3. Soap is manufactured by heating an oil or fat with a hot concentrated alkali. This process is called: A. neutralisation B. saponification C. polymerisation D. oxidation
Answer: B. Saponification produces soap and glycerol from a fat or oil and an alkali.
Q4. Besides soap, what is the other product of saponification? A. glycerol B. ethanol C. sodium chloride D. carbon dioxide
Answer: A. Saponification of a triglyceride gives soap and glycerol.
Q5. Sodium chloride is added at the end of soap making in order to: A. neutralise the alkali B. increase the temperature C. reduce the solubility of the soap so it separates out D. add flavour to the soap
Answer: C. This is salting out; the soap becomes less soluble and floats to the surface.
Q6. Which part of a soap molecule dissolves in grease? A. the hydrophilic head B. the hydrophobic tail C. the sodium ion D. the carboxylate group
Answer: B. The hydrophobic hydrocarbon tail is soluble in grease; the hydrophilic head dissolves in water.
Q7. Why does soap form a scum in hard water while detergent does not? A. Soap is a stronger alkali B. The calcium and magnesium salts of soap are insoluble, but those of detergent are soluble C. Detergent is made from oils D. Hard water contains no ions
Answer: B. Soap reacts with calcium and magnesium ions to form insoluble scum; a detergent’s equivalent salts stay soluble.
Q8. Which additive in a washing detergent keeps loosened dirt from settling back onto the cloth? A. drying agent B. whitening agent C. suspension agent D. fragrance
Answer: C. The suspension agent keeps the dirt suspended in the water so it is rinsed away.
Q9. Ascorbic acid is added to food mainly to act as: A. a colouring B. an antioxidant C. a sweetener D. a thickener
Answer: B. As an antioxidant it slows oxidation, preventing rancidity and browning.
Q10. Which statement about medicines is correct? A. Antibiotics are effective against viruses B. Analgesics are used to relieve pain C. All medicines are safe at any dose D. Antibiotics should be stopped as soon as you feel better
Answer: B. Analgesics relieve pain; antibiotics act on bacteria and the full course must be completed.
Paper 2 style: structured questions
Q11. Soap is made by saponification of vegetable oil. (a) Name the type of alkali used and the two products formed. (b) Explain, using the structure of a soap molecule, how soap removes greasy dirt from a piece of cloth.
Model answer. (a) A hot concentrated alkali such as sodium hydroxide is used. The two products are soap (the sodium salt of a fatty acid) and glycerol. (b) A soap ion has a hydrophobic tail that dissolves in grease and a hydrophilic head that dissolves in water. Soap first lowers the surface tension of the water so it wets the cloth. The tails dissolve into the grease while the heads stay in the water. Agitation breaks the grease into droplets, each surrounded by soap ions to form an emulsion. The droplets carry the same negative charge and repel one another, so they do not redeposit, and rinsing carries them away.
Q12. A consumer compares a bar of soap and a liquid detergent for washing clothes in an area with hard water. (a) State, with a reason, which product cleans more effectively in hard water. (b) Give one additive found in the detergent and state its function.
Model answer. (a) The detergent cleans more effectively, because it does not form scum with the calcium and magnesium ions in hard water, its calcium and magnesium salts are soluble, so it continues to lather and clean, while soap would be wasted forming scum. (b) Any one, for example: a water softener (builder) removes calcium and magnesium ions so the detergent works better; or a biological enzyme breaks down protein or fat stains; or a whitening agent makes white cloth appear whiter.
Q13. Modern materials and food additives are widely used by consumers. (a) Explain why a composite material such as reinforced concrete is used instead of ordinary concrete in construction. (b) Discuss one benefit and one risk of using food additives.
Model answer. (a) Reinforced concrete combines concrete with steel bars. Concrete is strong in compression but weak in tension, while steel is strong in tension; the composite is therefore strong under both compression and tension, making it suitable for beams and structures that ordinary concrete could not support. The property (combined strength) is linked directly to the use. (b) Benefit: additives such as preservatives extend shelf life and keep food safe to eat for longer; risk: excessive or unsuitable additives may harm health, which is why their use is regulated. A full answer gives both sides, not only the risk.
How to use these questions
Mark yourself honestly against each reason and model answer. In the structured questions, count the scoring points in the cleaning-action explanation and the property-to-use answers, those are where marks are won across this chapter. If any explanation feels incomplete, revisit the revision notes and worked examples, then try again. A one-to-one teacher can mark your full-length answers and point out any missing scoring point, which is the fastest way to turn partial marks into full marks in the SPM Chemistry written papers.
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