CBSE · Senior secondary

CBSE Class 11 — Notes, Chapters & Practice Quizzes

Master every Class 11 chapter — the base your board marks and your NEET / JEE / CUET prep both stand on.

13 subjects 171 chapters 177 practice quizzes NCERT syllabus
66 quiz attempts so far Dual AI-verified questions 10 quizzes free, then 10 credits
Notice Board
Class 11 students learning

Students preparing for CBSE Class 11 Annual Assessment

View all
Formula of the day
Chemistry · Gaseous State · 28 formulae in the cheatsheet
Trap of the day
In v² = u² + 2as, a is negative for deceleration — keep the sign or the stopping distance comes out wrong.

Chapter 1: Redox Reactions — Class 11 Chemistry

Chemistry · 9 chapters
Summary, key terms, important questions and a practice quiz with AI diagnosis for each.

Chapter 1: Redox Reactions

Try one from this chapter
In electronic terms, oxidation is defined as the:

Summary

Redox reactions, in which oxidation and reduction occur simultaneously, form a major class of chemical change underlying combustion, metallurgy, batteries and corrosion. The unit develops three parallel ways of viewing them. The classical idea defines oxidation as the addition of oxygen or an electronegative element, or the removal of hydrogen or an electropositive element, with reduction as the reverse. The electronic idea defines oxidation as loss of electrons and reduction as gain of electrons, so the oxidising agent accepts electrons (and is itself reduced) while the reducing agent donates them. Competitive electron-transfer experiments, such as zinc displacing copper from copper sulphate, establish a relative order of reactivity. The oxidation-number concept assigns oxidation states by a fixed set of rules and redefines oxidation as an increase, and reduction as a decrease, in oxidation number; this allows redox reactions to be classified into combination, decomposition, displacement and disproportionation types. Two systematic methods balance redox equations — the oxidation-number method and the half-reaction (ion-electron) method — applicable in both acidic and basic media, and redox titrations use self-indicators such as permanganate. Finally redox is linked to electrode processes through the redox couple, the Daniell cell and the standard electrode potential, the standard hydrogen electrode being assigned a value of exactly zero volts.

Classical idea of oxidation and reductionRedox in terms of electron transferOxidation number and its rulesTypes of redox reactionsBalancing by oxidation-number methodBalancing by half-reaction methodRedox titrationsRedox couples and electrode potential

Key terms

Oxidation
Loss of electrons by a species, equivalently an increase in its oxidation number.
Reduction
Gain of electrons by a species, equivalently a decrease in its oxidation number.
Oxidation number
The charge an atom would have if the bonding electrons were assigned to the more electronegative atom, fixed by a set of rules.
Disproportionation
A redox reaction in which an element in an intermediate oxidation state is simultaneously oxidised and reduced.
Redox couple
The oxidised and reduced forms of a substance taking part together in a half reaction, e.g. \(Zn^{2+}/Zn\).
Standard electrode potential
The potential of an electrode at unit concentration and 298 K, measured relative to the standard hydrogen electrode taken as zero.

Important questions

Explore interactively

Key-term flashcards
Flip cards · mark known · keyboard ← → and Space
6 cards
Term1 / 6
Oxidation
Tap to reveal
Meaning1 / 6
Loss of electrons by a species, equivalently an increase in its oxidation number.
Tap to flip back
Tap card to flip

Keyboard: ← → to move · Space to flip

Practice quiz · Redox Reactions

Score on this chapter, climb the leaderboard, and get an AI diagnosis of your mistakes.

Dual AI-verified questions Real exam pattern 2 quizzes free, then 10 credits per quiz

#1

Redox Reactions

Chemistry 10 Qs · ~10 min