Redox reactions — KCSE Chemistry
KCSE Chemistry · 26 practice questions · 3 syllabus objectives
What You'll Learn
Key learning outcomes for this topic, aligned to the KNEC KCSE syllabus.
Assign oxidation states to atoms in compounds and ions
Define oxidation and reduction in terms of electron transfer and change in oxidation number
Identify and explain redox reactions, oxidising agents and reducing agents
Sample Questions
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List the oxidation numbers for the following elements in their compounds: (a) phosphorus in H₃PO₄, (b) chromium in Cr₂O₇²⁻, (c) zinc in ZnCl₂, (d) hydrogen in H₂O. (4 marks)
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List the oxidation states of the following elements in their respective ions: (a) sodium in Na⁺, (b) sulfur in SO₄²⁻, (c) carbon in CO₂, (d) potassium in K₂Cr₂O₇. (4 marks)
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List the oxidation states of the following elements in their compounds: (a) chlorine in NaCl, (b) iron in Fe₂O₃, (c) nitrogen in NH₃, (d) manganese in KMnO₄. (4 marks)
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State the oxidation number rules for each of the following: (a) An uncombined element (e.g. O₂, Fe, Na). (1 mark) (b) A monatomic ion (e.g. Na⁺, Cl⁻, Fe³⁺). (1 mark) (c) Oxygen in most compounds. (1 mark) (d) Hydrogen in most compounds. (1 mark) (e) The sum of oxidation numbers in a neutral compound and in a polyatomic ion. (2 marks)
Why Practise Redox reactions?
KNEC Aligned
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