Eduqas A-Level Chemistry: Inorganic Chemistry overview

What this topic demands

The inorganic chemistry of the Eduqas Physical and Inorganic section combines quantitative redox analysis with the descriptive chemistry of the p-block and the d-block. The examiners reward accurate titration calculations, clear use of oxidation states, and precise explanations of complex ions and colour.

This guide walks through the inorganic topics in specification order and sets out the exam patterns Eduqas repeats. Each topic has a matching dot-point page with practice questions; this overview ties them together.

Redox in practice

Redox reactions (PI1.2) covers the two key redox titrations: manganate(VII), which is its own indicator (purple to colourless, with the first faint pink as the end point), and the iodine-thiosulfate titration with starch. You build balanced redox equations by combining half-equations so the electrons cancel, recognise disproportionation (the same element oxidised and reduced), and carry out titration calculations using the correct mole ratio.

The p-block and the halogens

Chemistry of the p-block (PI2.1) focuses on the halogens: their trends in volatility and oxidising power (which decreases down the group), displacement reactions, the reactions and tests of halide ions (silver nitrate, confirmed by ammonia solubility, and the concentrated-sulfuric-acid reactions), the disproportionation of chlorine in alkali, and the standard qualitative tests for carbonate, sulfate and halide anions.

The transition metals

Chemistry of the d-block transition metals (PI2.2) covers their definition (a stable ion with a partially filled $\text{d}$ sub-shell), their characteristic properties (variable oxidation states, coloured ions, catalysis and complex formation), the shapes of complex ions (octahedral and tetrahedral), the origin of colour through d-orbital splitting and the d-d transition, ligand substitution reactions, and their role as catalysts.

How this topic is examined

A typical Eduqas profile for the inorganic chemistry:

• Redox titrations. Manganate and thiosulfate calculations with the correct mole ratio, half-equation combination and disproportionation in terms of oxidation states.
• The halogens. Trends in oxidising power, displacement reactions, and the silver-nitrate halide test with ammonia confirmation.
• Anion tests. Carbonate, sulfate and halide identification, with the reason for acidifying first.
• Transition metals. Complex-ion formulae and shapes, the explanation of colour, ligand substitution and catalysis.

Check your knowledge

A mix of calculation, descriptive and explanation questions across the inorganic chemistry. Attempt them under timed conditions, then check against the solutions.

1. State the colour change at the end point of a manganate(VII) titration. (1 mark)
2. Define disproportionation. (1 mark)
3. Describe and explain the trend in oxidising power of the halogens down Group 7. (2 marks)
4. State the precipitate colours when silver nitrate is added to chloride, bromide and iodide solutions. (2 marks)
5. State three characteristic properties of transition metals. (3 marks)
6. Explain why aqueous copper(II) ions are coloured. (2 marks)