Chemistry in Everyday Life

Definition

Medicines are chemical substances used for the treatment of diseases and for reducing pain. When these chemicals are of low molecular masses, they interact with macromolecular targets in our body to produce a biological response. If this response is therapeutic and useful, these chemicals are called medicines.

Meaning of Pharmacotherapy and Chemotherapy

The use of chemicals for therapeutic effect is called pharmacotherapy, and the use of chemicals to cure microbial infections is known as chemotherapy.

Explanation

• Paracelsus' View: "All things are poison, and nothing is without poison; only the dosage makes a thing not a poison."
• Standard Definition: Medicines are substances or combinations of substances intended to treat or prevent disease in human beings or animals.
• Drugs interact with body receptors, enzymes, or macromolecules.
• Overuse leads to toxicity, while underuse fails to cure.

Definition & Meaning

Stomach acidity causes pain and irritation. Antacids are chemical substances (basic compounds) that neutralize excess acid in gastric juices and maintain a pH level appropriate for comfort.

Explanation

Hydrochloric acid helps digest food. Overeating, stress, or spicy food increases acid production, causing heartburn. Weak bases like sodium hydrogen carbonate, magnesium hydroxide, and aluminium hydroxide neutralize this excess. Modern drugs like cimetidine and ranitidine act as antihistamines to prevent acid release.

Examples

• Magnesium hydroxide (milk of magnesia).
• Aluminium hydroxide gel.

Real-Life Use

Students pulling an all-nighter surviving on spicy street food and coffee can experience burning chest sensations. A spoonful of milk of magnesia neutralizes excess hydrochloric acid for instant relief.

Definition & Meaning

Allergies are caused by histamine, a potent vasodilator released in the body. Antihistamines are drugs that interfere with the natural action of histamine by blocking histamine receptors.

Explanation

Histamine causes nasal congestion, itching, and bronchial constriction in asthma. Antihistamines block these actions. Note that antacids like cimetidine also belong here because they stop histamine from stimulating stomach acid release.

Examples

• Brompheniramine (dimetapp).
• Terfenadine (seldane).

Real-Life Use

Spring pollen triggers sneezing and runny noses. Taking brompheniramine blocks released histamines, drying nasal passages so you can focus in class.

Tranquilizers

Chemical compounds used for the treatment of stress, mental diseases, anxiety, and severe depression. They are central nervous system depressants (e.g., Equanil, Luminal).

Analgesics

Medicines that reduce or abolish pain without causing impairment of consciousness, mental confusion, or paralysis. Classified into non-narcotic (aspirin, paracetamol) and narcotic (morphine, codeine).

Examples

• Equanil (meprobamate) for anxiety.
• Paracetamol (crocin) for headaches.
• Morphine for post-surgical pain.

Meaning

Antimicrobials kill or inhibit microorganisms. This category includes antibiotics (produced or synthesized to destroy microbes), antiseptics (safe for living tissues like wounds), and disinfectants (applied to non-living objects like floors).

Examples

• Penicillin and Erythromycin (Antibiotics).
• Dettol (chloroxylenol and terpineol) and Tincture of iodine (Antiseptics).
• 1% Phenol (Disinfectant).

Meaning & Explanation

Chemical substances used to control birth rates and prevent pregnancy (oral contraceptives). They are mixtures of synthetic estrogen and progesterone derivatives (e.g., Norethindrone, Ethynylestradiol).

A. Artificial Sweetening Agents

Chemical compounds giving a sweet taste without adding calories. Examples: Aspartame (100x sweeter, unstable when heated), Saccharin (550x sweeter), Sucralose, Alitame (2000x sweeter).

B. Food Preservatives

Chemicals added to prevent spoilage due to microbial growth and rancidity. Example: Sodium benzoate used in soft drinks and sauces.

C. Antioxidants in Food

Substances preventing the oxidation of fats and oils. Examples: BHA (Butylated Hydroxyanisole) and BHT (Butylated Hydroxytoluene).

Soaps

Sodium or potassium salts of long-chain fatty acids made via saponification. Limitation: They form sticky scum in hard water due to calcium and magnesium ions.

Synthetic Detergents

Cleansing agents containing no soap, effective in both soft and hard water. Classified into Anionic (e.g., Sodium lauryl sulfate), Cationic (hair conditioners), and Non-ionic (dishwashing liquids).

Cleansing Action & Micelles

Soap molecules have a hydrophobic (oil-loving) tail and hydrophilic (water-loving) head. They form spherical clusters called micelles around grease particles, washing them away.

Hydrocarbon Tail (Hydrophobic) ~~~~~~~ COO- Na+ (Hydrophilic Head)
        

• High-Performance Liquid Chromatography (HPLC): Separates, identifies, and quantifies medicine mixtures.
• Mass Spectrometry (MS): Determines molecular weight and structure.
• Green Chemistry: Designs biodegradable surfactants to prevent water pollution.

Question: Calculate the mass of sodium hydroxide required to prepare soap completely from 890 grams of glyceryl tristearate fat. (Molar mass of glyceryl tristearate = 890 g/mol, NaOH = 40 g/mol).

Solution:

• Step 1: Balanced equation: $$\text{C}_{57}\text{H}_{110}\text{O}_{6} + 3\text{NaOH} \rightarrow \text{C}_{3}\text{H}_{5}(\text{OH})_{3} + 3\text{C}_{17}\text{H}_{35}\text{COONa}$$
• Step 2: 1 mole of fat requires 3 moles of $\text{NaOH}$.
• Step 3: Moles of fat = $\frac{890 \text{ g}}{890 \text{ g/mol}} = 1 \text{ mole}$.
• Step 4: Moles of $\text{NaOH}$ = $1 \times 3 = 3 \text{ moles}$.
• Step 5: Mass of $\text{NaOH}$ = $3 \text{ moles} \times 40 \text{ g/mol} = 120 \text{ g}$.

Answer: 120 grams of sodium hydroxide is required.

Viral colds bring multiple symptoms (fever, body aches, stuffy nose). Pharmaceutical companies design multi-symptom combination tablets:

• Paracetamol: Reduces fever and body aches.
• Diphenhydramine (Antihistamine): Dries nasal secretions and stops sneezing.
• Decongestant: Opens blocked sinuses.

Ingredients are blended with excipients, compressed, coated, and tested using HPLC for exact dosages, while BHA prevents moisture degradation during storage.

1. Which of the following is a non-narcotic analgesic?
   A) Morphine
   B) Codeine
   C) Aspirin
   D) Heroin
   Answer: C
   Explanation: Aspirin is non-narcotic and non-addictive for mild to moderate pain relief.
2. Dettol is a mixture of which two chemical compounds?
   A) Chloroxylenol and terpineol
   B) Phenol and iodine
   C) Bithional and cresol
   D) Formaldehyde and ethanol
   Answer: A
   Explanation: Dettol consists of chloroxylenol and terpineol.
3. Which artificial sweetener is unstable at cooking temperatures?
   A) Saccharin
   B) Sucralose
   C) Alitame
   D) Aspartame
   Answer: D
   Explanation: Aspartame breaks down at baking/cooking temperatures.
4. Soaps do not work well in hard water because:
   A) They dissolve too fast
   B) They form insoluble calcium and magnesium precipitates
   C) They react with sodium ions
   D) They increase water pH
   Answer: B
   Explanation: Ca and Mg ions form sticky scum instead of lather.
5. Which chemical prevents rancidity of fats?
   A) Sodium benzoate
   B) Aspartame
   C) BHA (Butylated Hydroxyanisole)
   D) Histamine
   Answer: C
   Explanation: BHA acts as an antioxidant.
6. Tranquilizers belong to which category of drugs?
   A) Antimicrobials
   B) Neurologically active drugs
   C) Antifertility drugs
   D) Antacids
   Answer: B
   Explanation: Tranquilizers affect the central nervous system to treat stress and anxiety.
7. Which cleansing agent works effectively in hard water without scum?
   A) Sodium palmitate
   B) Sodium stearate
   C) Sodium lauryl sulfate
   D) Potassium oleate
   Answer: C
   Explanation: Sodium lauryl sulfate is a synthetic detergent.
8. Who discovered penicillin?
   A) Louis Pasteur
   B) Alexander Fleming
   C) Paul Ehrlich
   D) Robert Koch
   Answer: B
   Explanation: Alexander Fleming discovered penicillin in 1928.
9. Antacids help relieve stomach discomfort by:
   A) Killing bacteria
   B) Neutralizing excess hydrochloric acid
   C) Coating teeth
   D) Increasing enzymes
   Answer: B
   Explanation: Antacids are weak bases neutralizing excess gastric acid.
10. Which category of detergents is used in hair conditioners?
    A) Anionic
    B) Cationic
    C) Non-ionic
    D) Natural soaps
    Answer: B
    Explanation: Cationic detergents possess germicidal properties suited for hair care.

1. Q: Why do soaps not form lather in hard water?
   Answer: Hard water contains soluble Ca and Mg salts. Soap reacts with these ions to form insoluble precipitates (scum) before lathering.
2. Q: Distinguish between an antiseptic and a disinfectant with one example each.
   Answer: Antiseptics are safe for living tissues (e.g., Dettol). Disinfectants are toxic to living tissues and used on non-living objects (e.g., 1% phenol).
3. Q: What are broad-spectrum antibiotics? Give an example.
   Answer: Antibiotics effective against a wide range of gram-positive and gram-negative bacteria (e.g., Ampicillin).
4. Q: Why are artificial sweeteners like aspartame recommended for diabetics?
   Answer: They provide sweetness without adding calories or raising blood glucose since they pass un-metabolized.
5. Q: What is saponification? Write the chemical reaction.
   Answer: Making soap by heating fats/oils with an aqueous alkali.
   $$\text{Fat} + 3\text{NaOH} \rightarrow \text{Glycerol} + 3\text{Soap}$$
6. Q: Why are cimetidine and ranitidine better antacids than sodium hydrogen carbonate?
   Answer: They block histamine receptors in the stomach wall, directly reducing acid production instead of giving temporary rebound neutralization.
7. Q: How do synthetic detergents differ from soaps regarding environmental impact?
   Answer: Branched synthetic detergents are often non-biodegradable and cause water pollution with persistent foam, whereas soaps decompose naturally.
8. Q: What is the difference between bactericidal and bacteriostatic antibiotics? Give examples.
   Answer: Bactericidal drugs kill bacteria (e.g., Penicillin), while bacteriostatic drugs inhibit their growth (e.g., Erythromycin).
9. Q: Explain the cleansing action of soaps using micelles.
   Answer: Hydrophobic tails dissolve in grease and hydrophilic heads face outward in water, forming spherical clusters called micelles that wash away easily.
10. Q: Why is saccharin preferred over sucrose by fitness enthusiasts?
    Answer: Saccharin is non-nutritive (zero calories), preventing weight gain associated with table sugar (sucrose).

• Medicines vs Drugs: Therapeutic biological responses are medicines; overuse causes toxicity.
• Antacids: Neutralize stomach acid (e.g., Milk of Magnesia).
• Analgesics: Relieve pain (Non-narcotic: Aspirin; Narcotic: Morphine).
• Soaps vs Detergents: Soaps fail in hard water; detergents work universally.

Mnemonic:
- **CID:** **C**idal **I**s **D**eadly (lethal bacteria killer).
- **SS:** **S**oap **S**cums in hard water; **DD:** **D**etergent **D**oes divinely in hard water.