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Redox Reactions

NCERT Class 11 Chemistry Chapter 7

Redox Reactions for Class 11 Chemistry, JEE and NEET: oxidation and reduction, oxidation numbers, balancing redox equations and electrode processes.

4 topics Updated 8 Nov 2026

For: Class 11, JEE and NEET

In the syllabus: JEE Class 11 syllabus, NEET Class 11 syllabus

With your textbook

NCERT Chemistry Part II (Class 11), Chapter 7 “Redox Reactions”, reprint 2026-27.

Open the official NCERT chapter (PDF, 1.9 MB, ncert.nic.in)

Checked on 19 Oct 2026.

Learn in this order

  1. Classical idea of redox reactions

    Classical definitions by oxygen and hydrogen, oxidising and reducing agents, NCERT Problem 7.1 solved.

    NCERT Section 7.1 12 min read 4 solved examples 8 practice questions

  2. Redox reactions as electron transfer

    Oxidation as loss of electrons, half reactions and the Zn, Cu, Ag order, with examples.

    NCERT Section 7.2 12 min read 4 solved examples 8 practice questions

  3. Oxidation number

    How to find it with the rules, Stock notation, types of redox reactions, balancing and titrations, solved.

    NCERT Section 7.3 29 min read 9 solved examples 12 practice questions

  4. Redox reactions and electrode processes

    Redox couples, salt bridge, anode and cathode signs and the E° table, solved.

    NCERT Section 7.4 15 min read 4 solved examples 9 practice questions

Key formulas in this chapter

Classical idea of oxidation and reduction

  • Oxidation: + O or electronegative element; − H or electropositive element
  • Reduction: − O or electronegative element; + H or electropositive element
  • Oxidising agent is reduced; reducing agent is oxidised

Redox reactions as electron transfer

  • Oxidation = loss of electrons; reduction = gain of electrons
  • Oxidising agent accepts electrons; reducing agent donates electrons
  • Electrons lost = electrons gained
  • Electron-releasing tendency: Zn > Cu > Ag

Oxidation number

  • Sum of oxidation numbers = 0 (compound) or the charge (ion)
  • Oxidation = increase in oxidation number; reduction = decrease
  • Common maximum: group number (1, 2) or group number − 10 (13–17); O and F are exceptions
  • Total increase in oxidation number = total decrease

Redox reactions and electrode processes

  • E⊖ of H+/H2 = 0.00 V by convention
  • Higher E⊖: stronger oxidising agent; lower E⊖: stronger reducing agent
  • E⊖(cell) = E⊖(cathode) − E⊖(anode); Daniell cell 1.10 V

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