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Playbook

Industrial and Applied Chemistry

28 q · 11% HARD. Industrial gases (water gas, producer gas, syngas), cement + glass composition, fertilisers (NPK), alloys (brass, bronze, solder, stainless steel), and paints + coatings (4 q · 75% HARD — the bank's most concentrated HARD pool, pigment/drier/thinner/anti-skinning).

questions in the bank
28
tagged HARD
11%
subtopic(s)
5
worked examples
2

When you’ll see it

An industrial-gas identification (water gas / producer gas / syngas), a cement/glass composition question, an NPK fertiliser name, an alloy composition match, or a paints + coatings additive role (pigment / drier / thinner / anti-skinning).

How this chapter is tested

28 q in 10 years · 11% HARD overall — but the HARD pool concentrates almost entirely in the Paints and Coatings subtopic (3 of 4 paint q are HARD = 75%). The rest of the chapter (Industrial gases, Cement/Glass, Fertilisers, Alloys) is straight recall, mostly EASY.

Industrial Gases (8 q): water gas = CO + H₂ (from steam over hot coke); producer gas = CO + N₂ (from air over coke); syngas = CO + H₂ from natural-gas reforming. Cement (Portland) = CaO + SiO₂ + Al₂O₃ + Fe₂O₃ + MgO. Glass = SiO₂ + Na₂CO₃ + CaCO₃ (soda-lime); coloured glass adds metal oxides (Fe → green, Co → blue, Cr → green, Mn → purple).

Paints and Coatings (4 q at 75% HARD) carries a specialised vocabulary: pigment (provides colour, e.g. TiO₂ white, PbO red); vehicle/binder (linseed oil); drier (catalyst speeds drying, e.g. naphthenates); thinner (reduces viscosity, e.g. turpentine); anti-skinning agent (prevents skin formation in tin, e.g. polyhydroxy phenol). The trap is mixing up roles — TiO₂ as drier (it's a pigment), turpentine as anti-skinning (it's a thinner).

The sub-skills

The rules and habits that decide whether you get a question right.

  • Industrial gas identification

    Water gas (CO + H₂) — fuel + synthesis. Producer gas (CO + N₂) — diluted, lower CV. Syngas (CO + H₂) — same as water gas from natural gas. Coal gas (H₂ + CH₄ + CO) — town gas, distillation of coal. LPG (propane + butane) — domestic fuel.

  • Cement + glass composition

    Portland cement: CaO (~64%), SiO₂ (~22%), Al₂O₃ (~6%), Fe₂O₃ (~3%), MgO (~2%). Soda-lime glass: SiO₂ + Na₂CO₃ + CaCO₃. Pyrex (borosilicate): SiO₂ + B₂O₃ (thermal-shock resistant). Lead crystal: SiO₂ + PbO (high refractive index).

  • NPK fertiliser breakdown

    N (nitrogen): urea CO(NH₂)₂, ammonium nitrate NH₄NO₃, ammonium sulphate (NH₄)₂SO₄. P (phosphorus): superphosphate of lime (Ca(H₂PO₄)₂ + CaSO₄), triple superphosphate. K (potassium): KCl, K₂SO₄. Mixed NPK fertilisers carry all three.

  • Alloy composition recall

    Brass = Cu + Zn (60/40 to 70/30). Bronze = Cu + Sn. Stainless steel = Fe + Cr (10–18%) + Ni (8–10%) ± C. Solder = Pb + Sn (60/40). Duralumin = Al + Cu + Mg + Mn (light, aircraft). Steel = Fe + C (<2%). Wrought iron = nearly pure Fe.

  • Paint additive roles

    Pigment = colour (TiO₂ white, PbO red, Cr₂O₃ green). Vehicle/binder = film-former (linseed oil, alkyd resin). Drier = oxidation catalyst (cobalt/manganese naphthenates). Thinner = viscosity reducer (turpentine, white spirit). Anti-skinning = prevents tin skin (polyhydroxy phenol). Filler = extends pigment (CaCO₃, talc).

2 worked examples from the bank

Real past-year questions illustrating the playbook. Click to reveal options + solution.

Example 1Industrial and Applied ChemistryHARD
Consider the following pairs: I. Pigment : TiO2\text{TiO}_2 II. Drier : Turpentine III. Thinner : Naphthenates IV. Antiskinning agent : Polyhydroxy phenol How many pairs are correctly matched?

[Q85 · Apr · 2026]

Example 2Industrial and Applied ChemistryMODERATE
Which of the following is/are physical test(s) employed for manufacture of paper? I. Mechanical and strength properties II. Surface properties III. Optical properties IV. Permeability to fluids

[Q89 · Apr · 2026]

Traps to expect

Distractor shapes specific to this chapter. The page-wide Traps section covers the bank-level patterns.

  • Pigment vs drier role swap

    TiO₂ is a pigment (provides white colour), NOT a drier. Naphthenates are driers, NOT thinners. Turpentine is a thinner, NOT an anti-skinning agent. The HARD pair-match questions deliberately swap one role to test exact recall.

  • Stainless steel without chromium

    Stainless steel REQUIRES chromium (≥ 10.5%) — the Cr₂O₃ passive layer is what makes it 'stainless.' Some HARD questions list 'which is NOT essential in stainless steel' with Cr in the option set as a trap.

  • Glass as 'crystalline solid'

    Glass is an AMORPHOUS solid (supercooled liquid), not crystalline. The trap option treats it as crystalline because we see 'glass' as solid-looking. Crystalline = ordered lattice (e.g. NaCl, quartz); amorphous = no long-range order (glass, plastic, rubber).

Drill every industrial and applied chemistry question

28 questions from the bank, scoped to 5 bundled subtopics.

Drill the 28 questions

Related playbooks

Often paired with this one — drill these next if you found the worked examples above tractable.