In terms of electron transfer, which statement correctly defines oxidation and reduction?
AOxidation is gain of electrons; reduction is loss of electrons
BOxidation is loss of electrons; reduction is gain of electrons
COxidation is addition of hydrogen; reduction is removal of hydrogen
DOxidation is decrease in oxidation number; reduction is increase
Answer & Solution
Correct answer: B. Oxidation is loss of electrons; reduction is gain of electrons
1. NCERT Ch 7 §7.2 defines the modern, electron-transfer view of redox.
2. Oxidation is the LOSS of electron(s) by any species (a useful mnemonic is OIL: Oxidation Is Loss).
3. Reduction is the GAIN of electron(s) by any species (RIG: Reduction Is Gain).
4. Option A reverses the two definitions. Option C states the older classical hydrogen-based view backwards. Option D inverts the oxidation-number rule (oxidation = increase in oxidation number).
_Source: NCERT Class 11 Chemistry Part 2, Ch 7 "Redox Reactions", §7.2, p. 2 ¶7._
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: