CourseCourseConceptConceptDocsDocuments

CAIE A-Level Chemistry AS 6.1.2 Changes in Oxidation Numbers to Help Balance Questions

Practise balancing redox and ionic equations using oxidation-number changes with CAIE 9701 AS questions and mark schemes.

Syllabus
2028–2030
Course
Chemistry 9701
Level
AS

Exam points

  • Use changes in oxidation numbers to balance redox equations and construct ionic equations.

CAIE A-Level Chemistry AS 6.1.2 Changes in Oxidation Numbers to Help Balance Questions question 1

[Maximum number: 1]

Oxygen can be prepared by the reaction of potassium manganate(VII), KMnO4\mathrm{KMnO}_{4}, hydrogen peroxide, H2O2\mathrm{H}_{2} \mathrm{O}_{2}, and sulfuric acid, H2SO4\mathrm{H}_{2} \mathrm{SO}_{4}. Each H2O2\mathrm{H}_{2} \mathrm{O}_{2} molecule loses two electrons in this reaction. The other products of the reaction are potassium sulfate, manganese(II) sulfate and water.

How many moles of oxygen gas are produced when 1.0 mol of KMnO4\mathrm{KMnO}_{4} reacts with an excess of H2O2\mathrm{H}_{2} \mathrm{O}_{2} in acidic conditions?

A

2.0 mol

B

2.5 mol

C

4.5 mol

D

5.0 mol

All question bank results loaded