Everyday Chemistry, Materials & Industrial Processes

Acids and Bases in Everyday Life

pH Scale

• pH measures the hydrogen ion concentration in a solution
• Scale runs from 0 to 14: pH < 7 = acidic; pH = 7 = neutral; pH > 7 = basic/alkaline
• A one-unit change in pH represents a 10-fold change in acidity/alkalinity (logarithmic scale)

pH of Common Substances

Antacids

Antacids work by neutralising excess hydrochloric acid (HCl) in the stomach:

• Milk of Magnesia: Mg(OH)₂ — reacts with HCl to form MgCl₂ + H₂O
• Aluminium hydroxide: Al(OH)₃ — less likely to cause laxative effect than magnesium salts
• Sodium bicarbonate: NaHCO₃ — quick but produces CO₂ gas (causes belching); not recommended for long-term use
• Calcium carbonate: CaCO₃ — fast-acting; however, "acid rebound" can occur

Acid rain: pH < 5.6; caused by SO₂ and NOₓ reacting with atmospheric moisture to form H₂SO₄ and HNO₃

Soaps and Detergents

Saponification — Making Soap

Saponification is the reaction between a fat/oil (triglyceride) and a strong alkali (NaOH or KOH):

• Fat + NaOH → Soap (sodium salt of fatty acid) + Glycerol
• Hard soaps: NaOH + fats → sodium stearate (solid soap)
• Soft soaps: KOH + fats → potassium stearate (liquid soap, shaving cream)

How Soap Works (Micelle Formation)

Soap molecules have two parts:

• Hydrophilic head (ionic, water-loving) — carboxylate end (–COO⁻ Na⁺)
• Hydrophobic tail (non-polar, oil-loving) — long hydrocarbon chain

When soap is added to water and oil, soap molecules arrange themselves into micelles — spherical clusters where hydrophobic tails surround the oil droplet and hydrophilic heads face the water. This suspends the oil in water (emulsification) and allows washing.

Soap vs Synthetic Detergent

Hard water contains Ca²⁺ and Mg²⁺ ions. Soap reacts with these to form precipitates (scum). Synthetic detergents do not form such precipitates.

Environmental concern with detergents: Branched-chain synthetic detergents are not biodegradable and cause foam formation in rivers and eutrophication (due to phosphates used as builders in detergents).

Polymers

A polymer is a large molecule made by joining many repeating small units (monomers) together.

Natural Polymers

Synthetic Polymers

Thermoplastic vs Thermosetting

Plastics and Environmental Policy

Single-Use Plastics Ban in India

The Environment (Protection) Act, 1986 and the Plastic Waste Management Rules, 2016 (amended 2022) form the legal framework.

Ban on specific single-use plastics from 1 July 2022:

• Plastic sticks for balloons, flags, candy/ice-cream sticks
• Plastic cutlery (plates, cups, glasses, spoons, knives, forks, straws)
• Plastic wrapping/packing films for invitation cards and cigarette packets
• Plastic cups and plates below 100 microns

Extended Producer Responsibility (EPR):

• EPR mandates that producers, importers, and brand owners are responsible for plastic packaging waste after it leaves the consumer
• EPR framework operationalised under Plastic Waste Management (Amendment) Rules, 2022
• Centralised EPR Portal managed by CPCB (Central Pollution Control Board)
• India has recycled 20.7 million tonnes of plastic packaging waste under EPR since 2022 (as reported to Parliament, March 2026)

Cement

Ordinary Portland Cement (OPC)

Raw materials: Limestone (CaCO₃) + Clay (silica, alumina, iron oxide) + Gypsum

Manufacturing process:

1. Crushing limestone and clay; mixing in proportions
2. Burning in a rotary kiln at ~1450°C → Clinker (calcium silicates, calcium aluminates, calcium aluminoferrite)
3. Grinding clinker with gypsum (3–5%) — gypsum controls the setting time

Hydration reaction (setting): Cement + water → calcium silicate hydrate (C-S-H gel) — this gel is responsible for hardness and strength

Types of Cement

Glass

Glass is an amorphous solid — atoms are arranged randomly (not crystalline).

Types of Glass

Fertilisers

India is the world's second-largest consumer of fertilisers (after China).

Major Fertilisers

Policy Initiatives

Neem-coated urea policy:

• Government mandated 100% neem coating of subsidised urea in 2015
• Neem oil coating slows release of nitrogen; reduces soil pollution; deters pilferage for industrial uses
• Has improved nitrogen use efficiency (NUE) by 10–15%

Nano Urea (IFFCO):

• Developed by IFFCO (Indian Farmers Fertiliser Cooperative)
• Nano Urea (Liquid) contains nitrogen particles of 20–50 nanometres in size embedded in organic matrix
• 4% nitrogen by weight (compared to 46% in conventional urea)
• World's first commercially produced nano urea fertiliser; IFFCO Aonla plant commissioned 21 December 2022
• Advantages: reduces conventional urea use by up to 50%; lower import bill; eco-friendly
• Applied by foliar spray rather than soil application
• Included in India's Fertilizer Control Order (FCO)

Pesticides

Pesticides are chemicals used to kill, repel, or control pests (insects, fungi, weeds, rodents).

Classification by Target Organism

Classification by Chemical Group

Stockholm Convention (2001) — Persistent Organic Pollutants (POPs)

• Bans or restricts 12 "dirty dozen" chemicals initially (including DDT, Aldrin, Dieldrin, PCBs)
• India ratified Stockholm Convention in 2006
• DDT banned in India for agricultural use; permitted only for vector control (malaria) in limited quantities

Industrial Chemistry — Key Processes

Haber-Bosch Process (Ammonia Synthesis)

• Reaction: N₂ + 3H₂ ⇌ 2NH₃
• Conditions: Temperature 450–500°C, pressure 150–300 atm, iron catalyst with potassium oxide and aluminium oxide as promoters
• Basis of all synthetic nitrogen fertilisers; one of the most important chemical processes in history
• Fritz Haber (discovery) + Carl Bosch (industrialisation) — both received Nobel Prizes

Contact Process (Sulphuric Acid)

• Step 1: S + O₂ → SO₂
• Step 2: 2SO₂ + O₂ ⇌ 2SO₃ (catalyst: V₂O₅/vanadium pentoxide; 400–600°C)
• Step 3: SO₃ + H₂SO₄ → H₂S₂O₇ (oleum) → H₂SO₄
• H₂SO₄ is the most produced industrial chemical; used in fertilisers, batteries, explosives, pharmaceuticals

Chlor-Alkali Process

• Electrolysis of brine (NaCl solution):
  • At cathode: 2H₂O + 2e⁻ → H₂ + 2OH⁻
  • At anode: 2Cl⁻ → Cl₂ + 2e⁻
• Products: Chlorine (Cl₂), Sodium hydroxide (NaOH), and Hydrogen (H₂)
• Uses: NaOH in paper, soap, textiles; Cl₂ for PVC, water treatment, solvents

Nanomaterials

Nanomaterials have dimensions in the 1–100 nanometre range (1 nm = 10⁻⁹ m). At this scale, materials exhibit unique physical and chemical properties different from their bulk counterparts.

Key Carbon Nanomaterials

Nanoparticles in Everyday/Medical Use

UPSC relevance: Nano fertilisers (Nano Urea — IFFCO), nano-drug delivery, nanomaterial safety regulations, Mission for Advancement in High-Impact Areas (MAHA) initiative

Green Chemistry

Green Chemistry (also called "sustainable chemistry") is the design of chemical processes and products that reduce or eliminate the use and generation of hazardous substances.

Coined by: Paul Anastas and John Warner (1998 book: Green Chemistry: Theory and Practice)

12 Principles of Green Chemistry (Anastas & Warner, 1998)

Atom economy = (Molecular weight of desired product / Total molecular weight of all products) × 100

Green chemistry in India: National Initiative on Green Chemistry (NIGC) under DST; Green Chemistry Award by Chemical Research Society of India (CRSI)

Dyes and Pigments

Natural dyes: Indigo (Indigofera tinctoria) — used for millennia; revived in organic textiles Synthetic dyes: Mauveine (William Perkin, 1856) — first synthetic dye; sparked the synthetic dye industry Azo dyes: Largest class of synthetic dyes (~50% of all dyes); contain –N=N– linkage; some are carcinogenic when metabolised

Food colours:

• Permitted in India (FSSAI): Tartrazine (yellow), Sunset Yellow, Carmoisine, Brilliant Blue, etc.
• Banned: Sudan dyes (used in chillies/palm oil — adulterants); Butter Yellow (carcinogenic)

Pharmaceuticals

Active Pharmaceutical Ingredient (API): The biologically active component of a drug that produces the therapeutic effect.

India as API hub:

• India produces ~20% of the world's generic medicines by volume
• India is the largest supplier of generic drugs globally — exports to 200+ countries
• India supplies ~60% of global vaccine demand (SERUM Institute, Bharat Biotech)
• India is the pharmacy of the developing world
• However, India is heavily import-dependent for bulk APIs — ~65–70% of API raw materials (Key Starting Materials, KSMs) imported from China
• PLI scheme for APIs (launched 2020): ₹6,940 crore incentive for domestic API manufacturing in 53 critical APIs across 41 products

Generic drugs vs branded drugs: Generic drugs contain the same API as branded versions but are sold at much lower prices after patent expiry; UPSC-relevant in context of access to medicines

Food Chemistry

FSSAI (Food Safety and Standards Authority of India): Statutory body under the Food Safety and Standards Act, 2006; Ministry of Health and Family Welfare; regulates food additives, labelling, and safety standards.

Common Food Additives

Maillard reaction: Non-enzymatic browning; reaction between amino acids and reducing sugars on heating; responsible for the flavour and colour of bread crust, roasted coffee, seared meat.

Previous Year Questions (PYQs)

Prelims

1. With reference to carbon nanotubes, which of the following statements is/are correct? (a) They can be used as carriers of drugs and antigens in the human body (b) They can be made into artificial muscles (c) They can be used in the processing of food items Which of the above statements are correct? (UPSC CSP 2020)

2. With reference to the use of nanomaterials, which one of the following statements is NOT correct? (a) Nanosized zinc oxide is used as a sunscreen lotion ingredient (b) Nano gold is used as a component in automotive catalytic converters (c) Nanosilver is used in water purification (d) Nano titanium dioxide is used as a food preservative (UPSC CSP 2019 — adapted)

3. Which of the following is NOT a greenhouse gas? (a) Methane (CH₄) (b) Nitrous Oxide (N₂O) (c) Carbon Dioxide (CO₂) (d) Nitrogen (N₂) (UPSC CSP 2016 — adapted)

4. Nano Urea (Liquid), launched by IFFCO, is primarily made using which technology? (a) Genetic modification of urea-producing bacteria (b) Nanotechnology — nano-sized nitrogen particles encapsulated in organic matrix (c) Microwave synthesis of ammonia (d) Electrolysis of ammonium nitrate (UPSC CSP 2022 — adapted)

Mains

1. What is Green Chemistry? Discuss any five of its twelve principles and explain how they contribute to sustainable development. (UPSC GS3 2018 — adapted)

2. India is called the "pharmacy of the world." Examine India's pharmaceutical sector with reference to API production, generic drugs, and the challenges of dependence on Chinese raw materials. (UPSC GS3 2021)

3. Discuss the environmental concerns associated with synthetic detergents and single-use plastics. What regulatory measures has India taken to address them? (UPSC GS3 2020 — adapted)

Exam Strategy

For Prelims:

• pH scale: 0–7 acidic, 7 neutral, 7–14 alkaline; blood pH = 7.35–7.45
• Saponification = fat + NaOH → soap + glycerol
• Soap fails in hard water; synthetic detergents work but are poorly biodegradable
• Thermoplastics (recyclable): PET, PVC, Nylon; Thermosetting (not recyclable): Bakelite, Melamine
• Haber-Bosch: N₂ + 3H₂ → 2NH₃; iron catalyst; 450–500°C, 150–300 atm
• Contact process (H₂SO₄): V₂O₅ catalyst
• Chlor-alkali: electrolysis of brine → Cl₂ + NaOH + H₂
• Green Chemistry: 12 principles by Anastas and Warner (1998)
• Nano Urea: IFFCO; 20–50 nm particle size; 4% N content; FCO approved
• Fullerenes (C₆₀), CNTs, Graphene — all carbon nanomaterials; graphene = strongest known material
• FSSAI: Food Safety and Standards Act, 2006; under Ministry of Health

For Mains:

• Link green chemistry to SDG 12 (Responsible Consumption and Production) and India's green manufacturing goals
• EPR for plastics is a strong policy example for environmental governance answers
• India's API dependence on China is a strategic vulnerability — link to Atmanirbhar Bharat and PLI scheme
• Nano fertilisers (Nano Urea) reduce India's urea import bill and subsidy burden — link to fiscal policy
• Food additives and FSSAI regulation: strong example for consumer protection and food security answers