AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.
Zinc is a metal of medium reactivity (middle of the activity series). Carbon can reduce zinc oxide because carbon has a greater affinity for oxygen than zinc at high temperatures:
$$\text{ZnO(s) + C(s)} \rightarrow \text{Zn(s) + CO(g)}$$
Sodium, however, is a highly reactive metal (top of the activity series). It has a much greater affinity for oxygen than carbon does, so carbon cannot reduce sodium oxide. Therefore, carbon reduction fails for sodium.
Instead, sodium is extracted by electrolytic reduction — electrolysis of molten sodium chloride, where sodium is deposited at the cathode:
$$\text{Na}^+ + e^- \rightarrow \text{Na}$$
The distinguishing property is reactivity (position in the activity series).
Source: Chapter 3, Sections 3.4.4 and 3.4.5
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Examiners look for three things: (1) identifying that zinc is mid-series and can be reduced by carbon, with the equation; (2) explaining why carbon fails for sodium — sodium's greater affinity for oxygen; (3) naming electrolysis as sodium's extraction method. Linking everything to "position in the activity series / reactivity" earns the reasoning mark. Don't just say "sodium is more reactive" — explain what that means for the reduction process.