Class 11 • Chemistry • Chapter 7
Redox Reactions
True & False Quiz
Oxidise. Reduce. Balance.
✓True
✗False
25
Questions
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Ch.7
Chapter
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XI
Class
Why True & False for Redox Reactions?
How this format sharpens your conceptual clarity
🔵 Redox reactions govern electron transfer processes — from batteries and corrosion to metabolism and industrial extraction of metals.
✅ T/F targets oxidation number rules, identifying oxidising/reducing agents, balancing equations (ion-electron and oxidation-number methods), and disproportionation.
🎯 In a disproportionation reaction, the SAME element is simultaneously oxidised and reduced — a single species acts as both oxidant and reductant.
📋
Read each statement carefully. Click True or False — instant feedback with explanation appears. Submit anytime; unattempted questions are marked Skipped.
Q 1
Oxidation is the process in which the oxidation number of an element increases.
Q 2
Reduction always involves a decrease in the oxidation number of an element.
Q 3
Oxidation and reduction can occur independently in a chemical reaction.
Q 4
In terms of electron transfer, oxidation is the loss of electrons.
Q 5
An oxidising agent donates electrons to another substance.
Q 6
A reducing agent undergoes oxidation during a redox reaction.
Q 7
The oxidation number of every free element is zero.
Q 8
The oxidation number of oxygen is always \(-2\) in all compounds.
Q 9
The oxidation number of hydrogen is \(-1\) in sodium hydride \((NaH)\).
Q 10
Fluorine always exhibits an oxidation number of \(-1\) in its compounds.
Q 11
The algebraic sum of oxidation numbers of all atoms in a neutral compound is zero.
Q 12
The oxidation number of carbon in \(CO_2\) is \(+4\).
Q 13
The oxidation number of manganese in \(KMnO_4\) is \(+7\).
Q 14
Stock notation represents the oxidation state of a metal using Roman numerals.
Q 15
\(FeCl_2\) is correctly named Iron(III) chloride in Stock notation.
Q 16
Every decomposition reaction is a redox reaction.
Q 17
The reaction \(Zn+CuSO_4\rightarrow ZnSO_4+Cu\) is a metal displacement redox reaction.
Q 18
In a disproportionation reaction, the same element is simultaneously oxidised and reduced.
Q 19
The decomposition of hydrogen peroxide is an example of disproportionation.
Q 20
In acidic medium, \(OH^-\) ions are added to balance hydrogen atoms during the half-reaction method.
Q 21
The Half-Reaction Method balances oxidation and reduction separately before combining them.
Q 22
Potassium permanganate acts as a self indicator in redox titrations.
Q 23
In a Daniell cell, electrons flow from the copper electrode to the zinc electrode through the external wire.
Q 24
A negative standard electrode potential indicates a stronger reducing agent than the standard hydrogen electrode.
Q 25
The modern concept of oxidation explains oxidation as a decrease in electron density around an atom.
Key Takeaways — Redox Reactions
Core facts for CBSE Boards & exams
1
Oxidation = loss of electrons / increase in oxidation number; Reduction = gain of electrons / decrease in oxidation number.
2
Oxidising agent gets reduced itself; Reducing agent gets oxidised itself.
3
Oxidation number of an element in its free/elemental state is always zero.
4
Sum of oxidation numbers of all atoms in a neutral compound = 0; in a polyatomic ion = charge on the ion.
5
Ion-electron method balances redox equations separately for oxidation and reduction half-reactions, then combines them by equalising electrons lost/gained.
6
Electrochemical series ranks elements by standard reduction potential; a species with higher E° is a stronger oxidising agent.
7
Disproportionation: one species is simultaneously oxidised and reduced (e.g., Cl₂ in cold dilute NaOH gives Cl⁻ and ClO⁻).