Inorganic Chemistry: Elements, Inorganic Compounds and Their Reactions
What you must understand
Know the properties and reactions of key elements: hydrogen, oxygen, halogens, nitrogen, sulfur, carbon, and important metals (alkali metals, alkaline earth metals, aluminium, iron, copper, zinc). Understand oxides (acidic, basic, amphoteric, neutral), hydroxides, acids and salts, and how they interconvert. Learn the reactivity series and displacement reactions.
Recognise common acids (HCl, H₂SO₄, HNO₃, H₃PO₄, H₂CO₃) and bases (NaOH, KOH, Ca(OH)₂, NH₃), plus salts (chlorides, sulfates, nitrates, carbonates, phosphates). Know typical preparation routes: metal + acid, oxide + acid, hydroxide + acid, precipitation. Know tests: flame tests, gas tests (CO₂ turns limewater milky; O₂ relights a glowing splint; H₂ gives a pop; NH₃ turns damp red litmus blue), and precipitation tests for halides and sulfates.
Understand oxidation states, redox, and common oxidising/reducing agents (KMnO₄, K₂Cr₂O₇, H₂O₂, SO₂). Link industrial processes: Haber, Ostwald, contact process, chlor-alkali, blast furnace.
Traps
Don't confuse oxidation with adding oxygen only - it means loss of electrons. Amphoteric species (Al₂O₃, Al(OH)₃, ZnO, Zn(OH)₂) react with both acids and bases. Watch for exceptions in the reactivity series (copper does not displace hydrogen from dilute acid).
Rule of thumb
Use the reactivity series to predict displacement; the more reactive metal displaces the less reactive one from solution.
Worked example
Zinc added to copper(II) sulfate: Zn + CuSO₄ → ZnSO₄ + Cu. Zinc is more reactive, so it displaces copper; the blue colour fades and a red-brown solid forms.