In the older, classical view of redox reactions (before electron-transfer was understood), OXIDATION was defined as which of the following?
AAddition of hydrogen (or any electropositive element) to a substance
BAddition of oxygen (or any electronegative element) to a substance
CRemoval of oxygen from a substance
DIncrease in the proton count of a nucleus
Answer & Solution
Correct answer: B. Addition of oxygen (or any electronegative element) to a substance
1. NCERT §7.1 traces the historical development of the term "oxidation".
2. The original meaning was literal: oxidation = adding oxygen (e.g. iron rusting to iron oxide). Later it was broadened to ANY more electronegative element (chlorine, sulfur, etc.).
3. So the classical view: oxidation = ADDITION of an electronegative element (oxygen being the prototype).
4. Option A is the classical view of REDUCTION (adding hydrogen). Option C is also the classical view of reduction (removing oxygen). Option D refers to a nuclear process, not a chemical redox.
_Source: NCERT Class 11 Chemistry Part 2, Ch 7 "Redox Reactions", §7.1, p. 1 ¶1-2._
Related questions
In KO₂ (potassium superoxide), the oxidation state of oxygen is:Hydrogen peroxide (H₂O₂) can act both as an oxidising agent AND as a reducing agent becausThe n-factor of KMnO₄ in acidic medium (Mn⁷⁺ → Mn²⁺) is:In the half-reaction 2 H₂O → O₂ + 4 H⁺ + 4 e⁻, water acts as:An element shows the SAME oxidation number in all its compounds. Which is it?Standard hydrogen electrode (SHE) is assigned electrode potential:Balance the skeleton equation MnO₄⁻ + Fe²⁺ + H⁺ → Mn²⁺ + Fe³⁺ + H₂O. The coefficient of MnIn an electrochemical (galvanic) cell, oxidation occurs at the: