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Substances in Daily Use & Applied Chemistry — Homi Bhabha Exam Chemistry MCQs with Solutions
Free Homi Bhabha Exam Chemistry Substances in Daily Use & Applied Chemistry MCQs with step-by-step solutions covering Soaps & Detergents, Polymers, Glass, Fertilizers, Air Composition, Water Purification. Practise online on Prepizo — no login needed.
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Sample questions with solutions
Q1 — Soaps & Detergents · hard · theory
Soap molecules remove oily dirt by forming tiny clusters called:
A. polymers
B. ions
C. micelles ✓ Correct
D. crystals
Solution: The soap tails dissolve in oil while the heads face water, forming micelles that lift dirt away.
Q2 — Soaps & Detergents · hard · theory
Soaps do not form a good lather with hard water because hard water contains:
A. excess soap
B. no minerals
C. calcium and magnesium salts ✓ Correct
D. only sodium salts
Solution: Ca²⁺ and Mg²⁺ ions react with soap to form an insoluble scum, so little lather forms.
Q3 — Soaps & Detergents · hard · theory
The process of making soap by reacting fats/oils with an alkali is called:
A. saponification ✓ Correct
B. neutralisation
C. polymerisation
D. fermentation
Solution: Saponification is the alkaline hydrolysis of fats/oils to produce soap and glycerol.
Q4 — Polymers · hard · theory
Which of the following is a natural polymer?
A. Nylon
B. Polythene
C. Cellulose ✓ Correct
D. PVC
Solution: Cellulose (in plants) is a natural polymer; the others are synthetic.
Q5 — Polymers · hard · theory
Plastics cause serious environmental problems mainly because they are:
A. easily burnt safely
B. natural
C. very expensive
D. non-biodegradable ✓ Correct
Solution: Most plastics are non-biodegradable, so they persist in the environment for a very long time.
Q6 — Glass · hard · theory
Glass is best described as a(n):
A. liquid
B. amorphous solid ✓ Correct
C. crystalline solid
D. gas
Solution: Glass lacks a regular crystal structure, so it is an amorphous (non-crystalline) solid.
Q7 — Glass · hard · theory
Toughened (safety) glass used in car windows is designed to:
A. break into small blunt pieces instead of sharp shards ✓ Correct
B. bend like rubber
C. conduct electricity
D. never break
Solution: Safety glass crumbles into small, relatively harmless granules, reducing injury.
Q8 — Fertilizers · hard · theory
Excessive use of chemical fertilizers can pollute water bodies and cause:
A. purer water
B. less algae
C. no effect
D. eutrophication (excess algal growth) ✓ Correct
Solution: Fertilizer run-off enriches water with nutrients, causing algal blooms (eutrophication) that harm aquatic life.
Q9 — Fertilizers · hard · theory
Fertilizers differ from manure in that fertilizers are:
A. always organic
B. free of nutrients
C. made from decomposed plant/animal waste
D. manufactured chemicals rich in specific nutrients ✓ Correct
Solution: Fertilizers are industrially produced and nutrient-specific, unlike organic manure.
Q10 — Air Composition · hard · theory
The approximate percentage of carbon dioxide in normal air is:
A. about 21%
B. about 10%
C. about 78%
D. about 0.04% ✓ Correct
Solution: CO₂ is a minor component, only about 0.03–0.04% of the air.
Q11 — Air Composition · hard · theory
The most abundant noble gas present in air is:
A. neon
B. krypton
C. helium
D. argon ✓ Correct
Solution: Argon makes up about 0.9% of the atmosphere — the most abundant noble gas in air.
Q12 — Water Purification · hard · theory
Chlorine is added to drinking water in a treatment plant mainly to:
A. add taste
B. kill disease-causing germs ✓ Correct
C. increase hardness
D. remove colour only
Solution: Chlorination disinfects water by killing bacteria and other pathogens.
Q13 — Water Purification · hard · theory
Reverse osmosis (RO) purifiers are used mainly to remove:
A. dissolved salts and impurities ✓ Correct
B. only large solid particles
C. only colour
D. oxygen
Solution: RO forces water through a semipermeable membrane, removing dissolved salts and fine impurities.
Q14 — Soaps & Detergents · medium · theory
Soap is chemically the sodium or potassium salt of:
A. nitric acid
B. carbonic acid
C. long-chain fatty acids ✓ Correct
D. mineral acids
Solution: Soaps are sodium/potassium salts of long-chain fatty acids.
Q15 — Soaps & Detergents · medium · theory
Detergents are preferred over soaps for washing in hard water because detergents:
A. form scum in hard water
B. do not clean
C. dissolve only in oil
D. work well even in hard water ✓ Correct
Solution: Detergents do not form scum with hard-water ions, so they clean effectively in hard water.
Q16 — Polymers · medium · theory
A polymer is a very large molecule made of many small repeating units called:
A. isotopes
B. ions
C. atoms only
D. monomers ✓ Correct
Solution: Polymers are formed by joining many small monomer units together.
Q17 — Polymers · medium · theory
Which of the following is a synthetic polymer?
A. Cotton
B. Nylon ✓ Correct
C. Wool
D. Silk
Solution: Nylon is a man-made (synthetic) polymer; cotton, silk and wool are natural.
Q18 — Polymers · medium · theory
A common plastic used to make bags and bottles is:
A. polythene ✓ Correct
B. bakelite only
C. rubber
D. nylon only
Solution: Polythene (polyethylene) is widely used for bags, bottles and packaging.
Q19 — Glass · medium · theory
The main raw material used to make ordinary glass is:
A. gypsum
B. limestone only
C. clay
D. sand (silica) ✓ Correct
Solution: Glass is made mainly from silica (sand), together with soda and limestone.
Q20 — Glass · medium · theory
Which property makes glass suitable for windows?
A. It is magnetic
B. It is flexible
C. It is transparent ✓ Correct
D. It is a good conductor of electricity
Solution: Glass is transparent, allowing light to pass through, which is ideal for windows.
Q21 — Glass · medium · theory
A useful environmental advantage of glass is that it is:
A. biodegradable within days
B. a good fuel
C. recyclable ✓ Correct
D. radioactive
Solution: Glass can be melted and re-used repeatedly, so it is recyclable.
Q22 — Fertilizers · medium · theory
The three main nutrients supplied by fertilizers to plants are:
A. carbon, oxygen and hydrogen
B. silicon, sulphur and lead
C. sodium, chlorine and iron
D. nitrogen, phosphorus and potassium ✓ Correct
Solution: N, P and K (the NPK nutrients) are the primary plant nutrients supplied by fertilizers.
Q23 — Fertilizers · medium · theory
Urea is a widely used ______ fertilizer:
A. nitrogenous ✓ Correct
B. micronutrient
C. phosphatic
D. potassic
Solution: Urea supplies nitrogen, so it is a nitrogenous fertilizer.
Q24 — Fertilizers · medium · theory
Compared with chemical fertilizers, manure is better for the soil because it:
A. adds humus and improves soil structure ✓ Correct
B. makes the soil hard
C. removes all nutrients
D. adds only nitrogen
Solution: Manure enriches the soil with organic matter (humus), improving its texture and fertility.
Q25 — Air Composition · medium · theory
The most abundant gas in the Earth's atmosphere is:
A. nitrogen ✓ Correct
B. argon
C. oxygen
D. carbon dioxide
Solution: Nitrogen makes up about 78% of the air by volume.
Q26 — Air Composition · medium · theory
The percentage of oxygen in the air is approximately:
A. 50%
B. 78%
C. 1%
D. 21% ✓ Correct
Solution: Oxygen makes up about 21% of the atmosphere.
Q27 — Air Composition · medium · theory
Which gas in the air is essential for the process of respiration and burning?
A. nitrogen
B. oxygen ✓ Correct
C. carbon dioxide
D. argon
Solution: Oxygen supports respiration and combustion.
Q28 — Water Purification · medium · theory
The settling down of heavy insoluble impurities in water on standing is called:
A. aeration
B. sedimentation ✓ Correct
C. evaporation
D. chlorination
Solution: In sedimentation, suspended solid impurities settle at the bottom.
Q29 — Water Purification · medium · theory
A simple household method to make water safe for drinking by killing microbes is:
A. colouring
B. shaking
C. freezing
D. boiling ✓ Correct
Solution: Boiling water kills most disease-causing microorganisms, making it safer to drink.
Q30 — Water Purification · medium · theory
Water that is safe and fit for drinking is described as:
A. distilled sea water only
B. hard water only
C. potable water ✓ Correct
D. polluted water
Solution: Potable water is clean water that is safe to drink.