NDA Chemistry · Free notes
Industrial and Applied Chemistry — NDA Chemistry
Industrial Chemistry is pure named-fact recall — 28 PYQs across 2017–2026, almost every one a 'which is correct / which is NOT' about a manufactured gas, a fertilizer, a building material, a paint additive, or an alloy. There is no derivation to do; the marks go to whoever has memorised the table. The chapter teaches in five movements, grouped by industry: (1) Industrial gases, manufacturing and reactions — water gas, syngas, the Haber process, acid-rain gases and airbag chemistry; (2) Fertilizers — the nutrient each fertilizer supplies (N, P or K), how superphosphate and nitrolim are made, and the urea traps; (3) Cement, glass and building materials — what glass and Portland cement are made from, and the property statements the bank loves to falsify; (4) Paints and coatings — the role of each additive (pigment, binder, drier, thinner, anti-skinning, antifoaming), the chapter's hardest pocket; (5) Common industrial substances and alloys — plaster of Paris, borax, soft soap, and the composition of solder. Most concepts are reference tables: learn the table, win the marks.
The handout has every subtopic, worked example, formula and trap with answers shown. The formula sheet is the chapter’s formulas and traps alone, on one page.
Subtopic notes
Industrial Gases, Manufacturing and Reactions
7 PYQsThe composition and use of the industrially important gas mixtures — water gas, syngas, producer gas — plus the Haber process for ammonia, the gases that cause acid rain, and the chemistry behind airbags.
Fertilizers
5 PYQsThe chemicals that supply the three plant nutrients — nitrogen (N), phosphorus (P) and potassium (K) — to soil, which nutrient each fertilizer carries, and how the common ones are manufactured.
Cement, Glass and Building Materials
7 PYQsWhat glass and Portland cement are actually made of — their raw materials, the chemical compounds inside set cement, and the property statements (glass is a supercooled liquid; pyrex beats soda glass) the bank loves to test.
Paints and Coatings
4 PYQsWhat each ingredient in a paint actually does — the pigment that colours, the binder that forms the film, the thinner that thins, the drier that speeds drying, and the additives (anti-skinning, antifoaming) that fix storage problems.
Common Industrial Substances and Alloys
5 PYQsThe composition of everyday industrial substances and alloys — plaster of Paris, borax, soft soap and solder — plus the raw materials of Portland cement, all answered by knowing one formula or element list per item.
Formula & revision sheet
0 formulas · 12 reference tables · 19 gotchas across all subtopics — the exam-eve cheat-sheet
Formula & revision sheet
0 formulas · 12 reference tables · 19 gotchas across all subtopics — the exam-eve cheat-sheet
Reference tables (3)
Water gas, syngas and producer gas4 rows
| Gas mixture | Composition | How it is made |
|---|---|---|
| Water gas (syngas) | CO + H₂ | Steam over red-hot coke Water gas and syngas are the SAME mixture: carbon monoxide + hydrogen. Do not pick CO + H₂O. |
| Producer gas | CO + N₂ | Limited air over red-hot coke |
| Coal gas | H₂ + CH₄ + CO | Destructive distillation of coal |
| Natural gas | Mainly CH₄ (methane) | Underground deposits |
Named manufacturing processes4 rows
| Product | Process | Key reaction / catalyst |
|---|---|---|
| Ammonia (NH₃) | Haber–Bosch | N₂ + 3H₂ → 2NH₃, iron catalyst Ammonia is manufactured by the Haber (Haber–Bosch) process. |
| Sulphuric acid (H₂SO₄) | Contact | 2SO₂ + O₂ → 2SO₃, V₂O₅ catalyst |
| Nitric acid (HNO₃) | Ostwald | Catalytic oxidation of ammonia |
| Washing soda (Na₂CO₃) | Solvay | Ammonia-soda process |
Applied gas facts — acid rain, airbags, atmosphere4 rows
| Phenomenon | Chemistry / fact | Answer the bank wants |
|---|---|---|
| Acid rain | SO₂ and NOₓ dissolve in rain | Sulphur dioxide (SO₂) The single biggest cause of acid rain in NDA options is sulphur dioxide. |
| Airbag inflation | 2NaN₃ → 2Na + 3N₂ | Sodium azide → nitrogen gas Airbags work by sodium azide decomposing into nitrogen gas. |
| 2nd most abundant atmospheric gas | N₂ ≈ 78%, O₂ ≈ 21% | Oxygen Nitrogen is first (most abundant); OXYGEN is second. |
| Paper physical testing | Mechanical, surface, optical, permeability | All four properties tested |
Watch out for (5)
- Water gas is CO + H₂, not CO + H₂O→ Water gas, syngas and producer gas
- Syngas = water gas→ Water gas, syngas and producer gas
- Haber makes ammonia; Contact makes sulphuric acid→ Named manufacturing processes
- Oxygen is second, nitrogen is first→ Applied gas facts — acid rain, airbags, atmosphere
- Airbags release nitrogen, not CO₂→ Applied gas facts — acid rain, airbags, atmosphere
Reference tables (2)
Which nutrient each fertilizer supplies6 rows
| Fertilizer | Nutrient supplied | Note |
|---|---|---|
| Urea | Nitrogen (N) | ≈ 46% N — highest-N solid fertilizer Urea is a NITROGEN fertilizer, not a phosphorus one. |
| Ammonium nitrate | Nitrogen (N) | Common N fertilizer |
| Ammonium sulphate | Nitrogen (N) | Common N fertilizer |
| Superphosphate of lime | Phosphorus (P) | Made from rock phosphate + H₂SO₄ |
| Muriate of potash (KCl) | Potassium (K) | Main K source |
| Ammonium sulphide ((NH₄)₂S) | None — not a fertilizer | A lab reagent Ammonium SULPHIDE is the odd one out — it is NOT used as a fertilizer (sulphate, nitrate and phosphate of ammonium all are). |
How superphosphate and nitrolim are made2 rows
| Fertilizer | Made from | Key fact |
|---|---|---|
| Superphosphate of lime | Calcium phosphate + sulphuric acid | Makes phosphate soluble Superphosphate = rock phosphate (calcium phosphate) treated with H₂SO₄. |
| Nitrolim (calcium cyanamide) | Calcium carbide (CaC₂) + nitrogen | Decomposes to ammonia in soil Nitrolim supplies nitrogen only, is inorganic, and is NOT an NPK fertilizer. |
Watch out for (3)
- Urea = nitrogen, never phosphorus→ Which nutrient each fertilizer supplies
- Ammonium sulphide is not a fertilizer→ Which nutrient each fertilizer supplies
- Nitrolim is N-only and inorganic→ How superphosphate and nitrolim are made
Reference tables (2)
Glass — nature and raw materials5 rows
| Aspect | Glass fact | Note |
|---|---|---|
| Physical nature | Amorphous, non-crystalline solid | Supercooled liquid; no definite melting point Glass is a non-crystalline amorphous solid — a supercooled liquid. |
| Source of silica | Sand (SiO₂) | The silica-providing raw material Sand is the source of silica in glass-making. |
| Other raw materials | Soda ash, limestone, borax | Borax → borosilicate (pyrex) |
| NOT a glass material | Gypsum (CaSO₄·2H₂O) | Belongs to cement/plaster, not glass Gypsum is the trap option — it is NOT used in making glass. |
| Pyrex vs soda glass | Pyrex is harder | Pyrex has boron oxide; heat-resistant 'Soda glass is harder than pyrex' is FALSE — pyrex (borosilicate) is the harder, more heat-resistant one. |
Portland cement — raw materials and compounds6 rows
| Aspect | Cement fact | Note |
|---|---|---|
| Raw materials | Lime, silica, alumina | + a little iron oxide Essential constituents of Portland cement: silica, alumina, lime. |
| Alite | 3CaO·SiO₂ | Tricalcium silicate |
| Belite | 2CaO·SiO₂ | Dicalcium silicate |
| Aluminate | 3CaO·Al₂O₃ | Tricalcium aluminate |
| NOT in cement | 4CaO·SiO₂ | No such silicate; only 3:1 and 2:1 4CaO·SiO₂ is the trap — it is NOT a standard cement compound. |
| Setting regulator | Gypsum (small amount) | Slows the setting time |
Watch out for (3)
- Pyrex is harder than soda glass→ Glass — nature and raw materials
- Gypsum is the glass trap→ Glass — nature and raw materials
- 4CaO·SiO₂ does not exist in cement→ Portland cement — raw materials and compounds
Reference tables (2)
Paint ingredients and their roles6 rows
| Role in paint | What it does | Correct example |
|---|---|---|
| Pigment | Colour + opacity | Titanium dioxide (TiO₂) TiO₂ is the standard white pigment; phthalocyanine is a blue/green pigment. |
| Binder (film-former) | Holds pigment, forms the film | Silicones (also resins / drying oils) Silicones are the binder; TiO₂, novolac and phthalocyanine in that question are pigment/resin distractors. |
| Thinner (solvent) | Thins the paint | Turpentine |
| Drier | Accelerates drying (oxidation) | Metal naphthenates Naphthenates are DRIERS, not thinners. Turpentine is the thinner. |
| Anti-skinning agent | Prevents skin in storage | Polyhydroxy phenol Anti-skinning agent = polyhydroxy phenol — not gelatin, pyridine or NMP. |
| Antifoaming agent | Stops foam in emulsion paint | Pine oil |
Emulsion paint additives — true/false facts3 rows
| Statement about emulsion paint | True or false | Why |
|---|---|---|
| Pine oil is used as antifoaming agent | True | Pine oil controls foam |
| Protective colloids decrease stability | False | They INCREASE stability Protective colloids stabilise the emulsion — they increase, not decrease, stability. |
| Oxidizable-oil driers accelerate drying | True | Oxidation speeds film formation |
Watch out for (4)
- Turpentine is the thinner; naphthenates are driers→ Paint ingredients and their roles
- Binder ≠ pigment→ Paint ingredients and their roles
- Anti-skinning agent = polyhydroxy phenol→ Paint ingredients and their roles
- Protective colloids INCREASE stability→ Emulsion paint additives — true/false facts
Reference tables (3)
Common alloys and their composition5 rows
| Alloy | Composition | Use |
|---|---|---|
| Solder | Lead (Pb) + tin (Sn) | Joining/soldering metals Solder is an alloy of lead and tin (Pb + Sn). |
| Brass | Copper + zinc (Cu + Zn) | Fittings, instruments |
| Bronze | Copper + tin (Cu + Sn) | Statues, coins, bearings |
| Steel | Iron + carbon (Fe + C) | Construction, tools |
| Duralumin | Al + Cu + Mg + Mn | Aircraft (light, strong) |
Plaster of Paris, borax and soft soap3 rows
| Substance | Formula / composition | Key fact |
|---|---|---|
| Plaster of Paris | CaSO₄·½H₂O | Calcium sulphate hemihydrate; from gypsum Plaster of Paris = CaSO₄·½H₂O (½ water per CaSO₄), not CaSO₄·2H₂O (that is gypsum). |
| Borax | Na, B, O, H (Na₂B₄O₇·10H₂O) | Sodium tetraborate decahydrate Borax contains sodium, boron, oxygen and hydrogen. |
| Soft soap | Potassium soap | Contains potassium (K) Soft soap = potassium salt; HARD soap = sodium salt. |
Raw materials of Portland cement4 rows
| Raw material | Provides | Source |
|---|---|---|
| Limestone | Lime (CaO) | Calcium carbonate rock |
| Clay / sand | Silica (SiO₂) | Clay, sand |
| Clay | Alumina (Al₂O₃) | Aluminosilicate clay |
| Iron ore + gypsum | Iron oxide; setting control | Added in small amounts Lime, silica and alumina are the essential trio — gypsum is only a setting regulator. |
Watch out for (4)
- Solder = Pb + Sn, brass = Cu + Zn, bronze = Cu + Sn→ Common alloys and their composition
- Soft soap = potassium, hard soap = sodium→ Plaster of Paris, borax and soft soap
- Plaster of Paris is ½ water, gypsum is 2 waters→ Plaster of Paris, borax and soft soap
- Lime + silica + alumina is the trio→ Raw materials of Portland cement
PYQ weightage by concept
12 concepts · 28 PYQs — where the marks actually sit, so you know what to drill first
PYQ weightage by concept
12 concepts · 28 PYQs — where the marks actually sit, so you know what to drill first
| Concept | PYQs | Share |
|---|---|---|
| Water gas, syngas and producer gas | 3 | 11% |
| Applied gas facts — acid rain, airbags, atmosphere | 3 | 11% |
| Named manufacturing processes | 1 | 4% |
| Concept | PYQs | Share |
|---|---|---|
| Which nutrient each fertilizer supplies | 3 | 11% |
| How superphosphate and nitrolim are made | 2 | 7% |
| Concept | PYQs | Share |
|---|---|---|
| Glass — nature and raw materials | 4 | 14% |
| Portland cement — raw materials and compounds | 3 | 11% |
| Concept | PYQs | Share |
|---|---|---|
| Paint ingredients and their roles | 3 | 11% |
| Emulsion paint additives — true/false facts | 1 | 4% |
| Concept | PYQs | Share |
|---|---|---|
| Plaster of Paris, borax and soft soap | 3 | 11% |
| Common alloys and their composition | 1 | 4% |
| Raw materials of Portland cement | 1 | 4% |
Test yourself on Industrial and Applied Chemistry
10 past NDA questions from this chapter, timed at 10 minutes and marked the way the exam marks it. You see your score and every answer the moment you finish. Free to start.