A-LevelChemistryChemical periodicity9701/12 · Oct/Nov 2025 · Q181 Mark

Compound X is an oxide of a Period 3 element. Compound X is a white solid at 25 °C. It reacts with water to form an acidic solution. What is compound X?

Aaluminium oxide

Bsilicon dioxide

Csulfur dioxide

Dphosphorus(V) oxide

✓ Correct answer

D: phosphorus(V) oxide

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Topic: Chemical periodicity, A-Level Chemistry (syllabus 9701). Multiple choice, 1 mark.
Source: A-Level Chemistry, Oct/Nov 2025 Paper 1 Variant 2, question 18.

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