The process of extraction of iron from its ore is

1. Analyze the question The question asks what type of chemical process takes place when iron is extracted from its ore (e.g. haematite, Fe₂O₃).

2. Explain the concept In ores, metals are usually combined with oxygen as oxides. To get the free metal, the metal ion must gain electrons, which means the metal is reduced. Reduction is the gain of electrons, or the removal of oxygen.

3. Step-by-step solution In the blast furnace:

• Coke (carbon) burns to form carbon(IV) oxide: C + O₂ → CO₂
• CO₂ reacts with more hot coke to form carbon(II) oxide, the reducing agent: CO₂ + C → 2CO
• Carbon(II) oxide removes oxygen from the iron(III) oxide: Fe₂O₃ + 3CO → 2Fe + 3CO₂

Here, Fe³⁺ in Fe₂O₃ gains electrons to become Fe (oxidation state +3 → 0). Iron is therefore reduced, while CO is oxidized to CO₂.

Checking the other options:

• A. Decomposition: the ore is not simply broken down by heat. A reducing agent is needed.
• B. Oxidation: this is the opposite of what happens to iron.
• D. Sublimation: this is a solid-to-gas change and has nothing to do with extraction.

4. Answer The correct option is C. reduction.

5. Exam tip Remember OIL RIG: Oxidation Is Loss, Reduction Is Gain (of electrons). Extracting any metal from its oxide ore is a reduction process. Metals low in the reactivity series, like iron, are reduced with carbon or CO, while very reactive ones, like sodium and aluminium, need electrolysis, which is also reduction at the cathode.