PRELIMS

Chemistry in Daily Life

Chemical compounds are integral to industrial processes, agriculture, and household activities.

Fertilizers

Added to soil to supply essential elements (N, P, K).

1. Nitrogenous: , Urea (46% Nitrogen), Sodium Nitrate ( ).
2. Phosphatic: Rock Phosphate [ ], Superphosphate of Lime, Triple Superphosphate.

Glass and Ceramics

Glass is a supercooled liquid mainly consisting of .

• Soda Glass: Composition / Feature: Sodium Calcium Silicate. Uses: Window panes, bottles (cheapest).
• Potash Glass: Composition / Feature: Potassium Silicate. Uses: Chemical apparatus (beakers, flasks).
• Optical Glass: Composition / Feature: . Uses: Lenses, prisms, telescopes.
• Crooks Glass: Composition / Feature: Contains rare metals. Uses: Lenses for UV protection.
• Flint Glass: Composition / Feature: Contains PbO. Uses: High-quality lenses and prisms.
• Lead Crystal: Composition / Feature: >24% PbO. Uses: Sparkles for decorative items.
• Borosilicate: Composition / Feature: Low alkali, high . Uses: High-temperature apparatus (Pyrex).
• Bulletproof: Composition / Feature: Glass + Polymer layers. Uses: Screens of car, train, aircraft.

• Colored Glass: Red (Selenium / ), Green (Chromium III), Blue (Cobalt II / ), Violet (Manganese IV).

Soaps and Detergents

• Soaps: Sodium or Potassium salts of higher fatty acids; made by Saponification (hydrolysis of fats/oils with NaOH/KOH). Sodium soaps are hard (bars); Potassium soaps are soft (liquid/shaving soaps).
• Detergents: Synthetic cleaning agents (sodium salts of sulphonic acids or ammonium/sulphonate salts) derived from petroleum hydrocarbons.
• Confused Pair — Soap vs. Detergent in Hard Water: Soaps react with ions in hard water to form an insoluble precipitate (scum), reducing lathering; Detergents do not form scum with hard water ions, so they lather and clean effectively even in hard water.

Medicinal Chemistry

1. Analgesics: Painkillers (Aspirin, Paracetamol, Morphine).
2. Antipyretics: Lowers body temperature (Paracetamol).
3. Antibiotics: Destroy bacteria (Penicillin).
4. Antiseptics: Kill/prevent microbe growth on living tissue (Boric Acid, Tincture of Iodine).
5. Antacids: Neutralize gastric HCl (Milk of Magnesia, Alum Phosphate).

Explosives

1. Dynamite (Nobel, 1863): Absorbed Nitro-glycerine in raw dust. Modern versions use .
2. TNT: Tri Nitro Toluene.
3. TNP (Picric Acid): Tri Nitro Phenol.
4. RDX: Highly explosive, contains Aluminium powder (plastisizer) to increase heat/speed.

Common/Household Names of Chemical Compounds

• Baking Soda: Sodium Bicarbonate ( )
• Washing Soda: Sodium Carbonate ( )
• Caustic Soda: Sodium Hydroxide ( )
• Caustic Potash: Potassium Hydroxide ( )
• Quick Lime: Calcium Oxide ( )
• Slaked Lime: Calcium Hydroxide ( )
• Lime Water: Dilute solution of Slaked Lime
• Gypsum: Calcium Sulphate dihydrate ( )
• Plaster of Paris: Calcium Sulphate hemihydrate ( )
• Epsom Salt: Magnesium Sulphate ( )
• Blue Vitriol: Copper Sulphate ( )
• Green Vitriol: Ferrous Sulphate ( )
• White Vitriol: Zinc Sulphate ( )
• Alum (Phitkari): Potassium Aluminium Sulphate ( )
• Common Salt: Sodium Chloride ( )
• Saltpetre: Potassium Nitrate ( )
• Chile Saltpetre: Sodium Nitrate ( )
• Dry Ice: Solid Carbon Dioxide ( )
• Laughing Gas: Nitrous Oxide ( )
• Marsh Gas: Methane ( )

High-Yield Factual Nuggets

• Aqueous Regia: (Dissolves gold).
• Tinctures: Iodine/Chlorine solutions for disinfection.
• Strategic Metal: Titanium (lighter than iron).
• Election Ink: Silver Nitrate ( ).
• Rat Poison: Zinc Phosphide.
• Gases: Phosgene ( - poisonous), Mustard Gas (Chlorine based), Laughing Gas ( - anaesthetic).
• Water Softening: Zeolite for permanent hardness.
• Fire Extinguisher: (Baking Soda) or .
• Bone Density: Bone is 58% Calcium Phosphate.

UPSC Relevance

"Applications of Science in Daily Life" is a staple in GS-III S&T.

• Medicine: Understanding the difference between analgesics (pain) and antipyretics (fever) and the importance of antibiotics.
• Consumer Goods: The composition of different glass types and the reason why "Crooks Glass" is used in sunglasses (UV).
• Agriculture: The N-P-K balance in fertilizers and the role of Urea as the first organic compound synthesized in a lab.