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Edexcel A-Level Chemistry AS 8.3 Indicate the Oxidation Number of an Element in a Compound or an Ion Questions

Use marked Edexcel IAL Chemistry questions to calculate oxidation numbers and write systematic chlorate and sulfate names with the correct Roman numerals.

Syllabus
First assessment 2019
Course
Chemistry YCH11
Level
AS

Exam points

  • Interpret a Roman numeral as the named element's oxidation number, not an ion charge.
  • Name chlorate or sulfate species by calculating and writing the correct Roman numeral.

Edexcel A-Level Chemistry AS 8.3 Indicate the Oxidation Number of an Element in a Compound or an Ion Questions question 1

[Maximum number: 1]

Chlorine dioxide, ClO2\mathrm{ClO}_{2}, can be used to treat water to make it safe for drinking. The molecule is a free radical. One suggested structure is shown.

Figure for Question Edexcel A-Level Chemistry AS 8.3 Indicate the Oxidation Number of an Element in a Compound or an Ion Questions question 1 — Edexcel A-Level Chemistry AS

Chlorine dioxide can be made from potassium chlorate(V), KClO3\mathrm{KClO}_{3}, in a two-step process.

Step 1 Potassium chlorate(V) reacts with concentrated sulfuric acid to form compound A.

Step 2 Compound A then undergoes a disproportionation reaction to form chlorine dioxide and hydrogen chlorate(VII), HClO4\mathrm{HClO}_{4}.

State the meaning of the Roman numerals in chlorate(V) and chlorate(VII).

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