Mastering Redox Reactions: Your Class 11 Chemistry MCQ Challenge

Question 1

What is the oxidation state of manganese (Mn) in $KMnO_4$?

Accepted Answer

+7

Answer

+5

Answer

+6

Answer

+4

Question 2

Which of the following reactions represents a reduction?

Accepted Answer

$Cl_2 \rightarrow 2Cl^{-}$

Answer

$Fe^{2+} \rightarrow Fe^{3+}$

Answer

$MnO_4^{2-} \rightarrow MnO_4^{-}$

Answer

$C_2H_4 \rightarrow C_2H_6$

Question 3

In the reaction $Zn(s) + CuSO_4(aq) \rightarrow ZnSO_4(aq) + Cu(s)$, which species is reduced?

Accepted Answer

$CuSO_4(aq)$

Answer

$Zn(s)$

Answer

$ZnSO_4(aq)$

Answer

$Cu(s)$

Question 4

An oxidizing agent is a substance that:

Accepted Answer

Gains electrons

Answer

Loses electrons

Answer

Undergoes oxidation

Answer

Has its oxidation state decreased

Question 5

What is the oxidation state of carbon in $CH_4$?

Accepted Answer

-4

Answer

+4

Answer

+2

Answer

-2

Question 6

Identify the type of redox reaction represented by $2KClO_3 \rightarrow 2KCl + 3O_2$.

Accepted Answer

Decomposition reaction

Answer

Combination reaction

Answer

Displacement reaction

Answer

Disproportionation reaction

Question 7

In the reaction $H_2S + Cl_2 \rightarrow 2HCl + S$, the reducing agent is:

Accepted Answer

$H_2S$

Answer

$Cl_2$

Answer

$HCl$

Answer

$S$

Question 8

Which of the following compounds has the highest oxidation state of nitrogen?

Accepted Answer

$HNO_3$

Answer

$NH_3$

Answer

$N_2O$

Answer

$NO_2$

Question 9

What is the sum of oxidation states of all atoms in a neutral molecule?

Accepted Answer

0

Answer

+1

Answer

-1

Answer

Equal to the charge of the most electronegative atom

Question 10

Which of the following reactions is NOT a redox reaction?

Accepted Answer

$NaOH + HCl \rightarrow NaCl + H_2O$

Answer

$2Na + Cl_2 \rightarrow 2NaCl$

Answer

$CuO + H_2 \rightarrow Cu + H_2O$

Answer

$CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O$

Question 11

When $SO_2$ is passed through acidified $K_2Cr_2O_7$ solution, the oxidation state of chromium changes from:

Accepted Answer

+6 to +3

Answer

+3 to +6

Answer

+6 to +2

Answer

+7 to +3

Question 12

How many electrons are involved in the reduction of one mole of $MnO_4^{-}$ to $Mn^{2+}$?

Accepted Answer

5

Answer

2

Answer

3

Answer

7

Question 13

Which of the following is an example of a disproportionation reaction?

Accepted Answer

$2H_2O_2 \rightarrow 2H_2O + O_2$

Answer

$N_2 + 3H_2 \rightarrow 2NH_3$

Answer

$Fe + S \rightarrow FeS$

Answer

$Zn + 2HCl \rightarrow ZnCl_2 + H_2$

Question 14

Balance the following reaction in acidic medium: $MnO_4^{-} + C_2O_4^{2-} \rightarrow Mn^{2+} + CO_2$. What is the coefficient of $H^+$ in the balanced equation?

Accepted Answer

16

Answer

8

Answer

5

Answer

10

Question 15

The oxidation state of iodine in $HIO_4$ is:

Accepted Answer

+7

Answer

+1

Answer

+5

Answer

-1

Question 16

Which of the following elements can exhibit both positive and negative oxidation states?

Accepted Answer

Chlorine

Answer

Fluorine

Answer

Oxygen

Answer

Sodium

Question 17

The reaction of $KI$ with $H_2SO_4$ to produce $I_2$, $SO_2$, $K_2SO_4$, and $H_2O$ is an example of:

Accepted Answer

Redox reaction

Answer

Combination reaction

Answer

Decomposition reaction

Answer

Metal displacement reaction

Question 18

Which species is acting as a reducing agent in the reaction: $2FeCl_3 + H_2S \rightarrow 2FeCl_2 + S + 2HCl$?

Accepted Answer

$H_2S$

Answer

$FeCl_3$

Answer

$FeCl_2$

Answer

$HCl$

Question 19

What is the oxidation state of oxygen in $OF_2$?

Accepted Answer

+2

Answer

-2

Answer

-1

Answer

+1

Question 20

For the reaction: $2AgNO_3(aq) + Cu(s) \rightarrow Cu(NO_3)_2(aq) + 2Ag(s)$, the correct statement is:

Accepted Answer

$Cu$ is oxidized and $Ag^+$ is reduced.

Answer

$Cu$ is reduced and $Ag^+$ is oxidized.

Answer

$NO_3^{-}$ is oxidized.

Answer

$AgNO_3$ is the reducing agent.

Question 21

Balance the following reaction in basic medium: $MnO_4^{-} + Br^{-} \rightarrow MnO_2 + BrO_3^{-}$. What is the coefficient of $OH^{-}$?

Accepted Answer

2

Answer

4

Answer

6

Answer

8

Question 22

Which of the following is the strongest reducing agent?

Accepted Answer

$I^{-}$

Answer

$F^{-}$

Answer

$Cl^{-}$

Answer

$Br^{-}$

Question 23

Consider the reaction: $Cr_2O_7^{2-} + X \rightarrow Cr^{3+} + H_2O$. The species X is an:

Accepted Answer

Reducing agent

Answer

Oxidizing agent

Answer

Acid

Answer

Base

Question 24

The sum of the oxidation numbers of sulfur in $Na_2S_2O_3$ is:

Accepted Answer

+2

Answer

+4

Answer

+6

Answer

+8

Question 25

The value of $n$ in the following equation: $Cr_2O_7^{2-} + 14H^+ + n e^{-} \rightarrow 2Cr^{3+} + 7H_2O$ is:

Accepted Answer

6

Answer

2

Answer

3

Answer

7

Question 26

How many moles of $KMnO_4$ are required to oxidize 1 mole of $FeSO_4$ in an acidic medium?

Accepted Answer

0.2

Answer

0.5

Answer

1

Answer

2

Question 27

Which of the following statements about oxidation number is INCORRECT?

Accepted Answer

The oxidation number of hydrogen is always +1 in all its compounds.

Answer

The oxidation number of an element in its free state is zero.

Answer

The oxidation number of fluorine is always -1 in all its compounds.

Answer

The algebraic sum of the oxidation numbers of all the atoms in a compound is zero.

Question 28

Consider the reaction: $ClO_3^{-} + I^{-} + H^{+} \rightarrow Cl^{-} + I_2 + H_2O$. When balanced, the stoichiometric coefficient for $I^{-}$ is:

Accepted Answer

6

Answer

1

Answer

3

Answer

5

Question 29

If an element is in its highest possible oxidation state, it can act only as:

Accepted Answer

An oxidizing agent

Answer

A reducing agent

Answer

Both oxidizing and reducing agent

Answer

Neither oxidizing nor reducing agent

Question 30

Identify the chemical change in which the oxidation number of a carbon atom does NOT change.

Accepted Answer

$CaC_2 \rightarrow Ca(OH)_2$

Answer

$CH_4 \rightarrow CO_2$

Answer

$CO \rightarrow CO_2$

Answer

$CH_4 \rightarrow CCl_4$

Questions in this Quiz

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Mastering Redox Reactions: Your Class 11 Chemistry MCQ Challenge

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