60 free MCQs on Chemistry in Everyday Life with worked answers and explanations. Drugs and how they interact with biological targets, chemicals in food, and cleansing agents (soaps and detergents) - chemistry applied directly to daily life and healthcare.
Take the timed Chemistry in Everyday Life chapterwise test →Below are 60 practice questions on Chemistry in Everyday Life, sorted Easy → Hard. Tap “Show answer & explanation” under any question to check yourself. Want the full theory first? Read the Chemistry in Everyday Life notes.
The hydrophobic hydrocarbon tail of each soap/detergent molecule dissolves into an oily dirt droplet, while the hydrophilic (ionic) head stays in the surrounding water - trapping the grease inside a micelle that rinses away with water.
Q1.
Which type of drug relieves pain without affecting consciousness?
Answer: B. Analgesic
Why: Analgesics relieve pain without affecting consciousness. Narcotic analgesics (e.g. morphine) and non-narcotic analgesics (e.g. aspirin) are the two main types.
Q2.
Antiseptics are applied to:
Answer: B. Living tissue, without harming it
Why: Antiseptics are applied to living tissue such as wounds and skin without damaging it, unlike disinfectants, which are used on inanimate objects.
Q3.
Which of these is a narcotic analgesic derived from opium?
Answer: C. Morphine
Why: Morphine is a narcotic analgesic derived from opium, used to relieve severe pain and as a surgical anaesthetic, but carries addiction risk.
Q4.
Antibiotics that completely kill bacteria are called:
Answer: B. Bactericidal
Why: Bactericidal antibiotics (e.g. penicillin) kill bacteria directly. Bacteriostatic antibiotics (e.g. erythromycin) only inhibit growth, relying on the immune system to clear the rest.
Q5.
Which type of synthetic detergent has a negatively charged hydrophilic head?
Answer: C. Anionic
Why: Anionic detergents have a negatively charged hydrophilic head, e.g. sodium lauryl sulphate, commonly used in toothpastes and shampoos.
Q6.
Soaps form scum (an insoluble precipitate) in hard water because they react with:
Answer: B. Ca<sup>2+</sup> and Mg<sup>2+</sup> ions
Why: Soaps form an insoluble precipitate with Ca<sup>2+</sup> and Mg<sup>2+</sup> ions present in hard water, reducing their cleaning efficiency. Synthetic detergents avoid this problem.
Q7.
Which food additive is added specifically to prevent the rancidity (oxidation) of fats and oils?
Answer: B. Antioxidant
Why: Antioxidants such as BHA and BHT are added to fatty foods to retard oxidation (rancidity), distinct from preservatives, which target microbial spoilage.
Q8.
Drugs that bring down a raised body temperature during fever are called:
Answer: D. Antipyretics
Why: Antipyretics are drugs, such as paracetamol and aspirin, that help lower body temperature during fever.
Q9.
Chemicals that are added to food to prevent its spoilage caused by microbial growth are called:
Answer: D. Food preservatives
Why: Food preservatives are substances added to food to prevent spoilage caused by microbial growth.
Q10.
A substance that increases the sweetness of food without adding significant calories is called:
Answer: C. An artificial sweetener
Why: Artificial sweeteners provide sweetness with little or no caloric value, unlike natural sugar.
Q11.
Drugs that lower body temperature during fever are called:
Answer: B. antipyretics
Why: Antipyretics such as paracetamol reduce fever.
Q12.
Drugs used to relieve pain are called:
Answer: B. analgesics
Why: Analgesics such as aspirin and morphine relieve pain.
Q13.
Chemicals applied to living tissue to kill or stop the growth of microbes are:
Answer: B. antiseptics
Why: Antiseptics are safe on living tissue; disinfectants are used on inanimate objects.
Q14.
A substance taken to neutralise excess acid in the stomach is an:
Answer: B. antacid
Why: Antacids such as magnesium hydroxide neutralise excess hydrochloric acid in the stomach.
Q15.
Aspirin is an example of a(n):
Answer: B. analgesic
Why: Aspirin is a non-narcotic analgesic (and antipyretic).
Q16.
Substances added to food to prevent it from spoiling are called:
Answer: B. preservatives
Why: Preservatives such as sodium benzoate inhibit the growth of microorganisms in food.
Q17.
Soaps are the sodium or potassium salts of:
Answer: B. fatty acids
Why: Soaps are made by the alkaline hydrolysis (saponification) of fats, which are esters of fatty acids.
Q18.
Unlike soaps, synthetic detergents work effectively even in:
Answer: B. hard water
Why: Detergents do not form insoluble scum with the Ca²⁺/Mg²⁺ ions of hard water, so they still lather.
Q19.
Antibiotics are medicines used to treat infections caused by:
Answer: B. bacteria
Why: Antibiotics act against bacteria; they are ineffective against viruses.
Q20.
Which of these is an artificial sweetener?
Answer: B. saccharin
Why: Saccharin is a synthetic, non-nutritive sweetener; the others are natural sugars.
Q21.
A drug that binds to a receptor and activates it, mimicking the body's natural chemical messenger, is called a(n):
Answer: B. Agonist
Why: An agonist binds a receptor and activates it just as the natural messenger would. An antagonist, by contrast, binds the receptor without activating it, blocking the natural messenger instead.
Q22.
Why do synthetic detergents work better than soaps in hard water?
Answer: B. The calcium and magnesium salts of detergents remain soluble in water, unlike the corresponding soap salts
Why: Soaps form an insoluble precipitate (scum) with Ca<sup>2+</sup>/Mg<sup>2+</sup> in hard water. Synthetic detergents' calcium and magnesium salts remain soluble, so they continue to clean effectively in hard water.
Q23.
Branched-chain alkylbenzene sulphonate detergents are considered more environmentally problematic than their straight-chain counterparts because they are:
Answer: B. Non-biodegradable, since bacterial enzymes cannot break down the branched chain efficiently
Why: Bacterial degradation works efficiently on unbranched hydrocarbon chains. Branching disrupts this enzymatic breakdown, so branched detergents persist in water bodies as pollutants, unlike straight-chain (linear) detergents.
Q24.
Ranitidine relieves acidity by which mechanism, distinguishing it from a simple antacid like milk of magnesia?
Answer: B. It blocks histamine H<sub>2</sub> receptors in the stomach lining, reducing acid secretion at the source
Why: Ranitidine is a histamine H<sub>2</sub>-receptor blocker: it reduces the secretion of stomach acid in the first place, rather than simply neutralising acid already present, as basic antacids like Mg(OH)<sub>2</sub> do.
Q25.
Cationic detergents, used mainly in hair conditioners and as germicides, differ from anionic detergents in which structural feature?
Answer: B. Their hydrophilic part carries a positively charged nitrogen atom instead of a negative sulphonate group
Why: Cationic detergents have a quaternary ammonium group with a positive charge as the hydrophilic part, unlike anionic detergents whose hydrophilic head carries a negative charge.
Q26.
Why are broad-spectrum antibiotics, such as tetracycline and chloramphenicol, sometimes used cautiously despite their effectiveness against a wide range of bacteria?
Answer: A. They act against several types of bacteria, which may also disturb the population of beneficial bacteria in the body
Why: Broad-spectrum antibiotics act against a wide range of gram-positive and gram-negative bacteria, so along with harmful bacteria they can also reduce populations of beneficial bacteria in the body.
Q27.
Soaps are generally biodegradable, but some synthetic detergents resist breakdown by microorganisms and accumulate in water bodies. What causes this difference in biodegradability?
Answer: B. Soaps have unbranched hydrocarbon chains that microbial enzymes break down readily, unlike branched detergent chains
Why: Soaps have straight hydrocarbon chains that are readily attacked by microorganisms, whereas detergents with highly branched chains resist microbial degradation and persist in water bodies as pollutants.
Q28.
Why are antacids like aluminium hydroxide or magnesium hydroxide used to treat hyperacidity rather than a strong base such as sodium hydroxide?
Answer: D. They are mild bases that neutralise excess stomach acid gently without damaging the stomach lining
Why: Antacids such as aluminium and magnesium hydroxide are mild bases that neutralise excess stomach acid gradually, unlike a strong base, which could harm the stomach lining.
Q29.
Why is sodium benzoate added to many soft drinks and food products in small, regulated quantities?
Answer: C. It acts as a preservative, slowing the growth of microorganisms that would otherwise spoil the drink
Why: Sodium benzoate is a common chemical preservative that inhibits the growth of bacteria, yeasts, and moulds, extending the shelf life of foods and beverages.
Q30.
Why do non-narcotic analgesics such as aspirin and paracetamol not cause addiction the way narcotic analgesics like morphine do?
Answer: A. They relieve pain mainly by reducing the production of prostaglandins rather than acting on opioid receptors in the brain
Why: Non-narcotic analgesics such as aspirin work mainly by inhibiting prostaglandin synthesis, while narcotic analgesics act on opioid receptors in the central nervous system, which is linked to tolerance and dependence.
Q31.
Tranquilisers are a class of drugs chiefly used to treat:
Answer: B. stress and anxiety
Why: Tranquilisers act on the central nervous system to relieve stress, anxiety and mild mental disorders.
Q32.
Ranitidine and cimetidine are widely used as:
Answer: B. antacids
Why: These H₂-receptor blockers reduce stomach acid secretion and act as modern antacids.
Q33.
Penicillin is a well-known example of a(n):
Answer: B. antibiotic
Why: Penicillin was the first widely used antibiotic, effective against many bacterial infections.
Q34.
A broad-spectrum antibiotic is one that is effective against:
Answer: B. a wide range of microbes
Why: Broad-spectrum antibiotics (e.g. chloramphenicol) act against many different kinds of bacteria.
Q35.
Antihistamines are drugs used mainly to relieve the symptoms of:
Answer: B. allergies
Why: Antihistamines counteract the effects of histamine, easing allergic reactions such as hay fever.
Q36.
The antiseptic Dettol is a mixture of chloroxylenol and:
Answer: B. terpineol
Why: Dettol contains chloroxylenol and terpineol as its active antiseptic ingredients.
Q37.
The cleansing action of soap depends on the formation of:
Answer: B. micelles
Why: Soap molecules cluster into micelles that trap grease in their hydrophobic centres, allowing it to be washed away.
Q38.
Sodium benzoate is added to foods and soft drinks as a:
Answer: B. a preservative
Why: Sodium benzoate is a common preservative that inhibits the growth of moulds and bacteria.
Q39.
A bactericidal antibiotic differs from a bacteriostatic one in that it:
Answer: B. kills the bacteria
Why: Bactericidal antibiotics (e.g. penicillin) kill bacteria, whereas bacteriostatic ones merely stop their growth.
Q40.
The artificial sweetener aspartame is limited to cold foods because it is:
Answer: B. unstable at cooking temperature
Why: Aspartame decomposes on heating, so it is unsuitable for cooking and baking.
Q41.
Phenol is used as both an antiseptic and a disinfectant. What determines which role it plays?
Answer: B. Concentration: a dilute solution (~0.2%) acts as an antiseptic on living tissue, while a more concentrated solution (~1%) acts as a disinfectant on inanimate objects
Why: The same chemical, phenol, is classified as an antiseptic or a disinfectant purely based on concentration and the surface it is applied to - dilute on living tissue (antiseptic), more concentrated on inanimate objects (disinfectant) where it would otherwise damage living cells.
Q42.
A competitive enzyme inhibitor must closely resemble the enzyme's natural substrate, but a receptor antagonist drug does not need to closely resemble the receptor's natural messenger. Why?
Answer: B. A competitive inhibitor must fit the same active site as the substrate, requiring structural resemblance; an antagonist only needs to occupy a site (or alter the receptor's shape) that blocks activation, which does not require mimicking the natural messenger
Why: Competitive inhibition specifically requires competing for the substrate's own binding site, so structural similarity to the substrate is what allows the inhibitor to fit there. An antagonist merely needs to block receptor activation, which can be achieved by binding a nearby site or altering the receptor's conformation allosterically, without resembling the natural messenger.
Q43.
Sulphonamide drugs act as antibacterials because they competitively inhibit the bacterial enzyme that uses para-aminobenzoic acid (PABA) to synthesise folic acid. Why does this strategy harm bacteria but spare human cells?
Answer: B. Human cells get folic acid from the diet and lack the enzyme pathway that synthesises it from PABA, unlike bacteria
Why: Bacteria must synthesise their own folic acid from PABA, and sulphonamides block this by mimicking PABA; humans obtain folic acid from food and do not rely on this enzyme pathway, so they are largely unaffected.
Q44.
Cimetidine and ranitidine are both H<sub>2</sub>-receptor antagonists used for acidity, yet they were developed to replace earlier antihistamines for allergies. Why don't ordinary (H1-blocking) antihistamines relieve stomach acidity?
Answer: B. Antihistamines for allergies block H1 receptors, while acid secretion in the stomach is controlled mainly through H<sub>2</sub> receptors
Why: Histamine acts on different receptor subtypes for different effects; H1 receptors mediate allergic responses while H<sub>2</sub> receptors on stomach lining cells stimulate acid secretion, so a drug must target H<sub>2</sub> specifically to reduce acidity.
Q45.
Polymers used to make biodegradable sutures, such as poly(beta-hydroxybutyrate-co-beta-hydroxyvalerate) (PHBV), break down inside the body over time. What structural feature of such polymers makes them susceptible to this breakdown, unlike polyethylene?
Answer: D. They contain ester linkages in the backbone that can be hydrolysed by water and enzymes present in body tissue
Why: Biodegradable polymers like PHBV have hydrolysable ester bonds in the main chain, so water and tissue enzymes can cleave them over time; polyethylene's all-carbon backbone resists such hydrolysis.
Q46.
Aspartame, a widely used artificial sweetener, is unsuitable for cooking at high temperatures and loses its sweetness over time in soft drinks. What is the chemical reason for this instability?
Answer: C. It is a dipeptide ester, and the peptide and ester bonds in it are hydrolysed by heat and moisture
Why: Aspartame is a methyl ester of a dipeptide (aspartic acid and phenylalanine), and both the peptide bond and ester bond can hydrolyse on heating or extended storage, breaking down the molecule and reducing sweetness.
Q47.
Tranquilizers and analgesics are both classified as drugs that act on the central nervous system, yet they are used for very different medical purposes. What distinguishes the primary action of a tranquilizer from that of an analgesic?
Answer: D. Tranquilizers reduce anxiety and mental tension by affecting brain neurotransmission, while analgesics mainly reduce the perception of pain
Why: Tranquilizers act on the central nervous system to relieve anxiety and stress, whereas analgesics primarily reduce pain sensation; both act on the CNS but target different effects.
Q48.
Soaps lose their cleansing action in hard water, but synthetic detergents derived from sodium salts of sulphonic acids continue to work. What underlying chemical difference explains why detergents are not affected the same way?
Answer: B. Calcium and magnesium salts of sulphonic acid detergents remain soluble in water, unlike the calcium and magnesium salts of fatty acids found in soap
Why: Soap's calcium and magnesium salts are insoluble and form scum, but the corresponding calcium and magnesium salts of detergents' sulphonate groups remain soluble in water, so detergents keep working in hard water.
Q49.
Artificial sweeteners like saccharin and sucralose are valued for diabetic and weight-conscious diets even though many are far sweeter than table sugar. What property must such a compound have to be useful as a sweetener despite this difference in sweetness intensity?
Answer: A. It must be non-nutritive, providing little caloric value, so tiny amounts match the sweetness of much more sugar
Why: Artificial sweeteners are typically non-nutritive, providing little to no caloric value, and are used in very small quantities because they are many times sweeter than sucrose, which makes them suitable for diabetics and dieters.
Q50.
Antioxidants such as BHT (butylated hydroxytoluene) are added to fats and oils to delay rancidity. At the molecular level, how do they slow down the oxidation process that causes rancid odours and flavours?
Answer: B. They donate hydrogen atoms to free radicals formed during autoxidation, interrupting the chain reaction
Why: Antioxidants like BHT readily give up a hydrogen atom to the free radicals generated during the autoxidation of fats, terminating the chain reaction and slowing the development of rancidity.
Q51.
Drugs that bind to the active site of an enzyme and block its normal function are enzyme:
Answer: B. inhibitors
Why: Enzyme inhibitors occupy or distort the active site, preventing the substrate from binding.
Q52.
The biological molecules most drugs target to produce their effect are usually:
Answer: B. proteins (enzymes or receptors)
Why: Most drugs act on proteins - either enzymes or cell-surface receptors - to alter a biological process.
Q53.
Anionic detergents have a long hydrocarbon chain ending in a:
Answer: B. negative sulfonate group
Why: Anionic detergents carry a negatively charged sulfonate or sulfate head, e.g. sodium alkylbenzenesulfonates.
Q54.
Which class of drug is used as an oral contraceptive (antifertility agent)?
Answer: B. synthetic hormones
Why: Antifertility drugs are synthetic derivatives of the hormones estrogen and progesterone.
Q55.
Which antibiotic acts mainly by inhibiting the synthesis of the bacterial cell wall?
Answer: B. penicillin
Why: Penicillin blocks the enzymes that build the bacterial cell wall, causing the cell to burst.
Q56.
Cationic detergents, which carry a positive charge, are used chiefly as:
Answer: A. germicides
Why: Cationic detergents (quaternary ammonium salts) have germicidal properties and are used in sanitisers and hair conditioners.
Q57.
Artificial sweeteners are valued in the food industry mainly because they:
Answer: B. sweeten without adding calories
Why: Non-nutritive sweeteners provide sweetness with little or no food value, useful for diabetics and dieters.
Q58.
A powerful narcotic analgesic that relieves severe pain but is habit-forming is:
Answer: B. morphine
Why: Morphine is a narcotic (opioid) analgesic; it relieves severe pain but can cause addiction.
Q59.
Older, non-biodegradable detergents pollute water because their hydrocarbon chains are:
Answer: B. highly branched
Why: Branched chains resist breakdown by microorganisms, so such detergents persist and foam in water bodies.
Q60.
A preservative commonly used in jams, squashes and pickles is:
Answer: B. sodium benzoate
Why: Sodium benzoate is a widely used chemical preservative in acidic foods such as jams and fruit squashes.