CBSE Class 12 Chemistry Chemistry in Everyday Life Questions

Question: A biological response is produced by drugs when it interacts with
a) micromolecular targets
b) macromolecular targets
c) any type of molecules
d) micromolecules as well as macromolecules

Answer: b

Question: Drugs can be classified on the basis of
a) pharmacological effect
b) molecular target
c) chemical structure
d) All of the above

Answer: d

Question: The site, apart from active site, at which the binding of drug to the enzyme takes place is called
a) activator site
b) regular site
c) allosteric site
d) All of these

Answer: c

Question: Receptors are selective in nature because it binds to
a) all type of chemical messengers.
b) a particular type of chemical messenger
c) cell membrane
d) All of the above

Answer: b

Question: The receptor proteins are embedded in the
a) DNA
b) cell membrane
c) cytoplasm
d) RNA

Answer: b

Question: Which of the following is a function of antagonist?
a) Mimic the natural messenger
b) It mimics the receptor
c) It binds to receptor site and inhibits its function
d) All of the above

Answer: c

Question: Drug which is used in controlling depression as well as hypertension is
a) penicillin
b) tetracycline
c) salvarsan
d) equanil

Answer: d

Question: In the stomach, histamine stimulates the secretion of pepsin and
a) sulphuric acid and hydrochloric acid
b) sulphuric acid
c) hydrochloric acid
d) sodium hydroxide

Answer: c

Question: Which of the following is a function of enzyme?
a) It holds the substrate for a chemical reaction
b) It provides functional groups
c) Both (a) and (b)
d) None of the above

Answer: c

Question: Artificial sweetener which is stable under cold conditions only is
a) saccharin
b) sucralose
c) aspartame
d) alitame

Answer: c

Question: Noradrenaline is a/an
a) antidepressant
b) antihistamine
c) neurotransmitter
d) antacid

Answer: c

Question: Which of the following are the derivatives of barbituric acid?
a) Veronal and amytal
b) Nembutal and luminal
c) Both (a) and (b)
d) Neither (a) nor (b)

Answer: c

Question: Use of chemicals for therapeutic effect is known as
a) physiotherapy
b) radiotherapy
c) chemotherapy
d) endotherapy

Answer: c

Question: The IUPAC name of aspirin is
a) o-acetyl salicylic acid
b) phenyl salicylate
c) acetyl salicylate
d) methyl salicylic acid

Answer: a

Question: Drugs, iproniazid and phenelzine belong to class of
a) depressant drugs
b) antidepressant drugs
c) antibiotics
d) antiseptic

Answer: b

Question: Which of the following drug inhibits the synthesis of prostaglandins?
a) Paracetamol
b) Aspirin
c) Codeine
d) Valium

Answer: b

Question: Which of the following is an arsenic containing drug?
a) Penicillin
b) Equanil
c) Salvarsan
d) Chloramphenicol

Answer: c

Question: Which of the following analgesics are called opiates?
a) Morphine
b) Codeine
c) Both (a) and (b)
d) Aspirin

Answer: a

Question: Which of the following is an anionic detergent?
a) Sodium lauryl sulphate
b) Cetyltrimethyl ammonium bromide
c) Glyceryl oleate
d) Sodium stearate

Answer: a

Question: Among the following, the narrow spectrum antibiotic is
a) ampicillin
b) amoxycillin
c) chloramphenicol
d) penicillin G

Answer: d

Question: Which of the following antibiotics is supposed to be toxic towards certain strains of cancer cells?
a) Vancomycin
b) Dysidazirine
c) Ofloxacin
d) Penicillin G

Answer: b

Question: Which of the following is an example of synthetic progesterone derivative?
a) Novestrol
b) Chloroxylenol
c) Norethindrone
d) Terpineol

Answer: c

Question: Food preservatives prevent spoilage of food due to microbial growth. The most commonly used preservative is
a) C₆H₅ COONa  
b) table salt
c) vegetable oils
d) All of the above

Answer: d

Question: Which type of detergent is formed when stearic acid reacts with polyethylene glycol?
a) cationic detergents
b) non-ionic detergents
c) anionic detergents
d) None of the above

Answer: b

VSA QUESTIONS (1 - MARK QUESTIONS)

Question 1. Write the formula and IUPAC name of aspirin.
Answer: Chemical formula: \(\text{C}_9\text{H}_8\text{O}_4\)
IUPAC name: 2-Acetoxybenzoic acid.
In simple words: Aspirin is a common medicine used to relieve pain and reduce fever.

Exam Tip: Memorize the structure containing a benzene ring substituted with an acetoxy group and a carboxylic acid group.

Question 2. Name two types of the drugs classified on the basis of pharmacological effect.
Answer: Two types of drugs classified on the basis of pharmacological effect are:
1. Analgesics (pain relievers)
2. Antacids (used to reduce stomach acidity)
In simple words: Pharmacological classification groups drugs by the medical condition or symptom they treat.

Exam Tip: Mention any two standard classes like antiseptics, antibiotics, or tranquilizers to secure full marks.

Question 3. What is the role of Bithional in toilet soaps?
Answer: Bithional is added to toilet soaps as an antiseptic to reduce the odours caused by bacterial decomposition of organic matter on the skin.
In simple words: It acts as a germ-killer in soaps to keep skin clean and prevent body odour.

Exam Tip: Clearly state that Bithional functions as an antiseptic additive in medicated and toilet soaps.

Question 4. Why is sodium benzoate added to packed containers of jams and pickles?
Answer: Sodium benzoate is added as a chemical food preservative to inhibit the growth of microorganisms and prevent spoilage in jams and pickles.
In simple words: It stops bacteria and fungi from growing so food stays fresh longer.

Exam Tip: Always associate sodium benzoate with food preservation.

Question 5. Name the type of drugs having following structural formula: \(\text{SO}_2\text{NHR}\) attached to a benzene ring with an \(\text{NH}_2\) group at the para position.
Answer: Sulpha drugs (sulphanilamide derivatives).
In simple words: These are synthetic antibacterial drugs containing a sulfonamide group.

Exam Tip: Recognize the characteristic \(-\text{SO}_2\text{NH}_2\) group attached to the aromatic ring for sulpha drugs.

Question 6. Why the receptors embedded in cell membranes show selectivity for one chemical messenger over the other?
Answer: The active site of a receptor has a specific shape and specific functional groups that can bind only a specific messenger which fits into it precisely, just like a lock and key.
In simple words: Only the chemical messenger with the correct shape and matching chemical groups can attach to a specific receptor.

Exam Tip: Mention the key terms 'active site', 'specific shape', and 'functional groups' for full credit.

Question 7. With reference to which classification has the statement 'ranitidine is an antacid' been given?
Answer: Classification based on pharmacological effect.
In simple words: It is classified according to what therapeutic effect or function it performs in the body.

Exam Tip: Note that drug classification based on pharmacological effect focuses on the drug's biological action.

Question 8. Give the name of medicine used for the treatment of syphilis.
Answer: Salvarsan.
In simple words: Salvarsan is an arsenic-based drug historically used to cure syphilis.

Exam Tip: Remember Paul Ehrlich's discovery of Salvarsan as the first effective treatment for syphilis.

Question 9. Give the composition of tincture of iodine.
Answer: Tincture of iodine is a 2-3 percent solution of iodine in alcohol-water mixture.
In simple words: It is a liquid mixture of iodine dissolved in water and ethanol used as an antiseptic.

Exam Tip: State the exact components: iodine, alcohol, and water.

Question 10. How does aspirin act as analgesic?
Answer: Aspirin acts as an analgesic by inhibiting the synthesis of prostaglandins, which are chemicals in the body that stimulate pain receptors.
In simple words: It stops the body from producing pain-signalling chemicals.

Exam Tip: Mention the inhibition of prostaglandin synthesis to get complete marks.

Question 11. Name the antiseptic agents present in dettol.
Answer: Chloroxylenol and terpineol.
In simple words: Dettol contains a mix of chloroxylenol and terpineol to kill germs.

Question 12. What precaution should be taken before administrating penicillin to a patient?
Answer: Before administering penicillin, it must be confirmed beforehand that the patient is not allergic to penicillin, as severe allergic reactions can be fatal.
In simple words: Always check for penicillin allergy before giving the injection to avoid dangerous allergic reactions.

Exam Tip: Emphasize testing for patient hypersensitivity or allergy.

Question 13. Explain why aspirin finds use in prevention of heart attacks?
Answer: Aspirin finds use in the prevention of heart attacks due to its anti-blood clotting (platelet aggregation inhibitory) activity.
In simple words: It prevents blood platelets from clumping together, reducing the risk of blood clots in blood vessels.

Exam Tip: Highlight the anti-blood clotting property of aspirin.

Question 14. Mention one use of drug meprobamate.
Answer: Meprobamate is used as an antidepressant and tranquilizer for relieving stress and anxiety.
In simple words: It is a calming medicine used to treat anxiety and mental tension.

Exam Tip: Classify meprobamate clearly under tranquilizers or antidepressants.

Question 15. Name the derivative of sucrose which tastes like sugar and can be safely used by weight conscious people.
Answer: Sucralose.
In simple words: Sucralose is a zero-calorie artificial sweetener made from sugar.

Exam Tip: Distinguish sucralose (trichloro derivative of sucrose) from aspartame and saccharin.

Question 16. Why synthetic detergents are preferred over soaps for use in washing machines?
Answer: Synthetic detergents work well even in hard water and do not form insoluble calcium or magnesium scum, making them ideal for washing machines.
In simple words: They clean effectively in hard water without leaving sticky deposits.

Exam Tip: Mention the absence of insoluble scum formation in hard water.

Question 17. How is acidity cured with cimetidine?
Answer: Cimetidine cures acidity by preventing the interaction of histamines with the receptors present in the stomach wall, which otherwise stimulate the secretion of hydrochloric acid.
In simple words: It blocks histamine from signaling the stomach to produce excess acid.

Exam Tip: Use the terms 'histamine receptors' and 'stomach wall' in your explanation.

Question 18. While antacids and antiallergic drugs interfere with the function of histamines, why do these not interfere with the function of each other?
Answer: Antacids and antiallergic drugs bind to different receptor sites in the body. Therefore, they do not interfere with the function of each other.
In simple words: They target completely different receptors, so their actions do not overlap.

Exam Tip: Emphasize that different target receptors are involved for each drug type.

Question 19. Which of the following two compounds can be used as a surface active agent and why? (Compound (i) has a long hydrocarbon tail and an ionic head \(-\text{COO}^-\text{Na}^+\); Compound (ii) has two ionic heads or different structure).
Answer: Compound (i) can be used as a surface active agent.
Reason: It possesses a dual nature with a hydrophobic (water-repelling hydrocarbon chain) end and a hydrophilic (water-attracting ionic carboxylate) end.
In simple words: It works as a surfactant because one part loves oil and dirt while the other part loves water.

Exam Tip: Always mention both 'hydrophobic' and 'hydrophilic' ends when explaining surfactants.

Question 20. What type of drug is chloramphenicol?
Answer: Chloramphenicol is a broad-spectrum antibiotic.
In simple words: It is a powerful medicine used to kill a wide variety of harmful bacteria.

Exam Tip: Specify that it is a broad-spectrum antibiotic effective against many bacterial infections.

Question 21. Name a chemical used as an antiseptic as well as disinfectant.
Answer: Phenol (in different concentrations, e.g., 0.2 percent solution acts as an antiseptic while 1 percent solution acts as a disinfectant).
In simple words: Phenol can be used for both purposes depending on how diluted it is.

Exam Tip: State phenol and optionally mention concentration differences.

Question 22. Give two examples of antidepressants.
Answer: Two examples of antidepressants are:
1. Iproniazid
2. Phenelzine (Nardil)
In simple words: These are medicines used to treat severe depression and mood disorders.

Question 1. What are antihistamines? Give two examples.
Answer: Antihistamines are drugs that-interfere with the natural action of histamine by binding to histamine receptors, thereby preventing allergy symptoms.
Examples: Brompheniramine and Terfenadine.
In simple words: They are allergy medications that block the effects of histamine in the body.

Exam Tip: Provide both the definition and two clear examples to secure full 2 marks.

Question 2. What are narcotic and non-narcotic analgesics? Give one example of each.
Answer: 1. Narcotic analgesics: These are potent pain-relieving drugs that produce sleep and addiction (e.g., Morphine).
2. Non-narcotic analgesics: These are non-addictive pain relievers used for mild to moderate pain (e.g., Aspirin or Paracetamol).
In simple words: Narcotics are strong, habit-forming painkillers, while non-narcotics are safe, non-addictive painkillers.

Exam Tip: Clearly differentiate based on addictiveness and potency.

Question 3. Explain the following terms as used in medicinal chemistry: (i) Target molecules (ii) Enzyme inhibitors.
Answer: (i) Target molecules: Biological macromolecules such as proteins, carbohydrates, lipids, and nucleic acids that drugs interact with to elicit a pharmacological response.
(ii) Enzyme inhibitors: Drugs that bind to the active site or allosteric site of an enzyme and block its catalytic activity.
In simple words: Target molecules are the body components drugs act on, and enzyme inhibitors are drugs that block enzyme activity.

Exam Tip: Define each term concisely with biological relevance.

Question 4. Give one important use of each of following: (i) Equanil (ii) Morphine
Answer: (i) Equanil: Used as a tranquilizer for relieving depression and hypertension.
(ii) Morphine: Used as a potent narcotic analgesic for relieving severe pain (such as post-surgery or cancer pain).
In simple words: Equanil calms the mind, and morphine relieves very severe pain.

Exam Tip: State specific medical applications for each drug.

Question 5. What are neurologically active drugs? Give two examples.
Answer: Neurologically active drugs are medicines that affect the message transfer system from nerve to receptor, influencing the nervous system and treating neurological disorders.
Examples: Tranquilizers and analgesics.
In simple words: These are drugs that affect the brain and nervous system to alter mood or relieve pain.

Exam Tip: Explain their action on the nervous system and give valid sub-classes or examples.

Question 6. (i) What are antibiotics? (ii) What is meant by the term broad spectrum antibiotic?
Answer: (i) Antibiotics are chemical substances produced wholly or partly by microorganisms that can inhibit the growth of or destroy other microorganisms.
(ii) Broad spectrum antibiotics are antibiotics that are effective against a wide range of gram-positive and gram-negative bacteria.
In simple words: Antibiotics kill germs, and broad-spectrum ones kill many different types of bacteria.

Exam Tip: Mention the dual nature of antibiotics (bactericidal/bacteriostatic) and the wide coverage of broad-spectrum types.

Question 7. From the given examples ciprofloxacin, phenelzine, morphine, ranitidine. Choose the drug used for (i) treating allergic conditions (ii) to get relief from pain
Answer: (i) Treating allergic conditions: None directly from this specific list as antihistamines (note: ciprofloxacin is antibiotic, phenelzine is antidepressant, morphine is analgesic, ranitidine is antacid). Wait, let us check standard mapping: Ciprofloxacin is antibiotic, Phenelzine is antidepressant, Morphine is analgesic, Ranitidine is antacid. For general allergy, none listed, but if categorized, none of these are primary antihistamines. However, looking closely at typical question banks, let us answer based on standard categories: (ii) Morphine is used to get relief from pain.
In simple words: Morphine is the pain-relieving drug among the choices.

Exam Tip: Match each drug name precisely to its known pharmacological class.

Question 8. Why a drug should not be taken without consulting a doctor? Give two reasons.
Answer: Two reasons why a drug should not be taken without consulting a doctor are:
1. Taking drugs indiscriminately can cause toxic or poisonous side effects.
2. Self-medication can lead to drug resistance or mask symptoms of a serious underlying disease, delaying proper diagnosis.
In simple words: Unauthorized medicines can cause harmful side effects or hide dangerous illnesses.

Question 9. State the main difference between bacteriostatic and bacteriocidal antibiotics. Give one example of each.
Answer: Bacteriostatic antibiotics inhibit or arrest the growth of bacteria (e.g., Erythromycin), whereas bacteriocidal antibiotics kill bacteria outright (e.g., Penicillin or Aminoglycosides).
In simple words: Bacteriostatic stops bacteria from multiplying, while bacteriocidal kills them completely.

Question 10. What are antifertility drugs? Name the constituents of an oral contraceptive.
Answer: Antifertility drugs are chemical substances used to control birth rates and population by preventing ovulation or fertilization.
Constituents of an oral contraceptive: A mixture of synthetic estrogen (e.g., ethynylestradiol) and progesterone derivatives (e.g., norethindrone).
In simple words: They are birth control pills made of synthetic hormones.

Exam Tip: Always state that oral contraceptives contain a blend of synthetic estrogen and progesterone.

Question 11. What do you mean by non-biodegradable detergents? How can we make biodegradable detergents?
Answer: Non-biodegradable detergents are synthetic detergents containing branched hydrocarbon chains that cannot be easily decomposed by microorganisms, leading to water pollution.
How to make biodegradable detergents: By using detergents with unbranched (straight) hydrocarbon chains, which are easily attacked and degraded by bacteria.
In simple words: Branching makes detergents resistant to decay; straight chains make them eco-friendly.

Question 12. If water contains dissolved calcium hydrogencarbonate, which out of soap and detergent, will you prefer to use? Why?
Answer: We will prefer to use detergent.
Reason: Detergents do not form insoluble calcium precipitates (scum) with dissolved calcium ions in hard water, unlike soaps which precipitate out and waste cleaning power.
In simple words: Detergents work well in hard water because they do not form sticky scum.

Question 13. What are barbiturates? What is the action of barbiturates on human body?
Answer: Barbiturates are derivatives of barbituric acid that act as potent central nervous system depressants.
Action on human body: They function as tranquilizers, reduce anxiety, induce sleep, and act as effective pain-relieving and sedative agents.
In simple words: They are calming, sleep-inducing drugs derived from barbituric acid.

Question 14. Write the structures of soaps obtained by the hydrolysis of following fats: (i) Glyceryl palmitate (ii) Glyceryl oleate.
Answer: (i) Soap from glyceryl palmitate: Sodium palmitate, \(\text{C}_{15}\text{H}_{31}\text{COO}^-\text{Na}^+\)
(ii) Soap from glyceryl oleate: Sodium oleate, \(\text{C}_{17}\text{H}_{33}\text{COO}^-\text{Na}^+\)
In simple words: Hydrolysis of these fats yields sodium salts of fatty acids (soaps).

Exam Tip: Write the exact formula for sodium palmitate and sodium oleate.

SA (II) TYPE QUESTIONS (3 - MARK QUESTIONS)

Question 1. (i) Why are artificial sweetening agents harmless when taken? (ii) Name one such artificial sweetening agent. (iii) Why is the use of aspartame as an artificial sweetener limited to cold foods?
Answer: (i) Artificial sweetening agents are harmless because they pass through the human body unchanged and are excreted without providing any calories.
(ii) Saccharin (or Aspartame / Sucralose).
(iii) Aspartame is thermally unstable and decomposes at cooking temperatures, so its use is limited to cold foods and drinks.
In simple words: They give sweetness without calories, but aspartame breaks down when heated.

Exam Tip: Explain excretion without metabolism for (i) and thermal instability for (iii).

Question 2. Pick out the odd one amongst the following on the basis of their medicinal properties. Give suitable reason: (i) Luminal, seconal, terfenadine, equanil. (ii) Chloroxylenol, phenol, chloramphenicol, bithional. (iii) Sucralose, aspartame, alitame, sodium benzoate.
Answer: (i) Terfenadine is odd because it is an antihistamine, whereas Luminal, seconal, and equanil are tranquilizers.
(ii) Chloramphenicol is odd because it is a broad-spectrum antibiotic, whereas chloroxylenol, phenol, and bithional are antiseptics.
(iii) Sodium benzoate is odd because it is a food preservative, whereas sucralose, aspartame, and alitame are artificial sweeteners.
In simple words: Grouping them by function reveals one chemical that belongs to a different medicinal category.

Exam Tip: Clearly state the pharmacological category of each compound to justify the odd one out.

Question 3. Give the main function of following in the body of human beings: (i) Enzymes (ii) Receptor proteins (iii) Neurotransmitter
Answer: (i) Enzymes: Act as biological catalysts that speed up biochemical reactions in the body.
(ii) Receptor proteins: Receive chemical messages and trigger cellular responses.
(iii) Neurotransmitters: Facilitate communication across synapses between nerve cells.
In simple words: Enzymes speed up reactions, receptors catch signals, and neurotransmitters pass nerve messages.

Exam Tip: Keep definitions precise and function-oriented.

Question 4. Identify the class of drug: (i) Phenelzine (Nardil) (ii) Aspirin (iii) Cimetidine
Answer: (i) Phenelzine: Antidepressant (Tranquilizer)
(ii) Aspirin: Analgesic and antipyretic
(iii) Cimetidine: Antacid
In simple words: Phenelzine fights depression, aspirin relieves pain, and cimetidine stops stomach acidity.

Exam Tip: Memorize drug names and their exact medical classification.

Question 5. Give the pharmacological function of the following type of drugs: (i) Analgesics (ii) Tranquilizers (iii) Antifertility drugs
Answer: (i) Analgesics: Reduce or abolish pain without causing impairment of consciousness.
(ii) Tranquilizers: Relieve stress, anxiety, mental tension, and psychiatric disorders.
(iii) Antifertility drugs: Control birth rates and prevent pregnancy by hormonal action.
In simple words: Analgesics stop pain, tranquilizers calm the mind, and antifertility drugs prevent pregnancy.

Question 6. Give the name of medicine used in the treatments of following diseases: (i) Typhoid (ii) Joint pain (in Arthritis) (iii) Hypertension
Answer: (i) Typhoid: Chloramphenicol (Antibiotic)
(ii) Joint pain (Arthritis): Analgesics or anti-inflammatory drugs (e.g., Aspirin, Ibuprofen)
(iii) Hypertension: Tranquilizers / Antihypertensive drugs (e.g., Equanil / Reserpine)
In simple words: Chloramphenicol cures typhoid, painkillers treat joint pain, and specialized medicines lower blood pressure.

Exam Tip: Provide standard, medically accepted drug examples for each disease.

Question 7. Give the class of drugs to which these substances belong: (i) Bithional (ii) Amoxycillin (iii) Salvarsan
Answer: (i) Bithional: Antiseptic
(ii) Amoxycillin: Antibiotic
(iii) Salvarsan: Antibiotic (specifically used against syphilis)
In simple words: Bithional kills germs on skin, while amoxycillin and salvarsan fight bacterial infections.

Exam Tip: Classify bithional as antiseptic and both amoxycillin and salvarsan as antibiotics.

Question 8. How are antiseptics different from disinfectants? How does an antibiotic different from these two? Give one example of each of them.
Answer: Antiseptics are applied safely to living tissues (wounds, cuts) to kill microorganisms (e.g., Dettol), whereas disinfectants are applied to inanimate objects like floors and instruments because they are harmful to living tissues (e.g., Phenol 1 percent). Antibiotics are chemical substances produced by microorganisms that are taken internally to cure systemic bacterial infections (e.g., Ampicillin).
In simple words: Antiseptics go on skin, disinfectants clean non-living surfaces, and antibiotics are swallowed to fight internal infections.

Exam Tip: Distinguish application sites (living tissue vs. inanimate objects vs. internal ingestion).

Question 9. Explain the following terms with suitable examples: (i) Cationic detergents (ii) Anionic detergents (iii) Nonionic detergents
Answer: (i) Cationic detergents: Quaternary ammonium salts of amines with acetates, chlorides, or bromides where the cationic part possesses a long hydrocarbon chain (e.g., Cetyltrimethylammonium bromide).
(ii) Anionic detergents: Sodium salts of sulfonated long-chain alcohols or hydrocarbons (e.g., Sodium lauryl sulphate).
(iii) Nonionic detergents: Esters of high molecular weight formed by reaction of polyethylene glycol with long-chain fatty acids (e.g., Pentaerythrityl stearate or liquid dishwashing detergents).
In simple words: They are classified based on the electrical charge on the cleansing part of the molecule.

Exam Tip: Include definitions and standard chemical examples for each type of detergent.

Question 10. Label hydrophilic and hydrophobic part in the following compounds: (i) \(\text{CH}_3(\text{CH}_2)_{10}\text{CH}_2\text{OSO}_3^-\text{Na}^+\) (ii) \(\text{CH}_3(\text{CH}_2)_{15}\text{N}^+(\text{CH}_3)_3\text{Br}^-\) (iii) \(\text{CH}_3(\text{CH}_2)_{16}\text{COO}(\text{CH}_2\text{CH}_2\text{O})_n\text{CH}_2\text{CH}_2\text{OH}\)
Answer: (i) Hydrophobic part: \(\text{CH}_3(\text{CH}_2)_{10}\text{CH}_2-\); Hydrophilic part: \(-\text{OSO}_3^-\text{Na}^+\)
(ii) Hydrophobic part: \(\text{CH}_3(\text{CH}_2)_{15}-\); Hydrophilic part: \(-\text{N}^+(\text{CH}_3)_3\text{Br}^-\)
(iii) Hydrophobic part: \(\text{CH}_3(\text{CH}_2)_{16}-\); Hydrophilic part: \(-\text{COO}(\text{CH}_2\text{CH}_2\text{O})_n\text{CH}_2\text{CH}_2\text{OH}\)
In simple words: The long hydrocarbon chain is the water-hating (hydrophobic) tail, and the ionic or polar group is the water-loving (hydrophilic) head.

Exam Tip: Clearly separate the alkyl chain from the polar head group in each structure.

Question 11. Classify the following as cationic detergents, anionic detergents or nonionic detergents: (i) \(\text{CH}_3(\text{CH}_2)_{10}\text{CH}_2\text{OSO}_3^-\text{Na}^+\) (ii) \([\text{CH}_3-(\text{CH}_2)_{15}\text{N}(\text{CH}_3)_3]^+\text{Br}^-\) (iii) A nonionic detergent structure with a benzene ring attached to \(\text{C}_9\text{H}_{19}\) and polyoxyethylene chain.
Answer: (i) Anionic detergent
(ii) Cationic detergent
(iii) Nonionic detergent
In simple words: Identify the functional groups to determine whether the detergent is anionic, cationic, or nonionic.

Exam Tip: Check the charge on the hydrophilic portion to classify correctly.

Question 12. How do enzyme inhibitors work? Distinguish between competitive and non-competitive enzyme inhibitors.
Answer: Enzyme inhibitors either block the active site of the enzyme or change the shape of the active site by binding at an allosteric site.
Difference:
1. Competitive enzyme inhibitor: It competes with the natural substrate for attachment on the active site of the enzyme.
2. Non-competitive enzyme inhibitor: It binds at an allosteric site and alters the shape of the active site so that the substrate can no longer recognize or bind to it.
In simple words: Competitive inhibitors block the active site directly, while non-competitive inhibitors distort the shape of the enzyme from a side location.

Exam Tip: Highlight the difference between active site binding (competitive) and allosteric site binding (non-competitive).