Grade 11 : Chemistry - Redox Reactions (Set 2)

Question 1

In terms of electron transfer, oxidation is defined as:

Accepted Answer

A) Loss of electrons

Answer

B) Gain of electrons

Answer

C) Gain of protons

Answer

D) Loss of protons

Question 2

What is the oxidation number of nitrogen in nitric acid ($HNO_3$)?

Accepted Answer

C) +5

Answer

A) +3

Answer

B) +4

Answer

D) -3

Question 3

Consider the reaction: $CuO(s) + H_2(g) \rightarrow Cu(s) + H_2O(l)$

Which substance acts as the oxidizing agent in this reaction?

Accepted Answer

B) CuO

Answer

A) $H_2$

Answer

C) Cu

Answer

D) $H_2O$

Question 4

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

Accepted Answer

D) +7

Answer

A) +2

Answer

B) +4

Answer

C) +6

Question 5

Which of the following half-reactions represents a reduction process?

Accepted Answer

B) $Cl_2 + 2e^- \rightarrow 2Cl^-$

Answer

A) $Fe^{2+} \rightarrow Fe^{3+} + e^-$

Answer

C) $Na \rightarrow Na^+ + e^-$

Answer

D) $2S^{2-} \rightarrow S_2 + 4e^-$

Question 6

Calculate the oxidation number of chromium in potassium dichromate ($K_2Cr_2O_7$).

Accepted Answer

A) +6

Answer

B) +3

Answer

C) +5

Answer

D) +7

Question 7

A redox reaction in which the same chemical species is simultaneously oxidized and reduced is termed a:

Accepted Answer

D) Disproportionation reaction

Answer

A) Combination reaction

Answer

B) Metal displacement reaction

Answer

C) Neutralization reaction

Question 8

What is the oxidation state of oxygen in hydrogen peroxide ($H_2O_2$)?

Accepted Answer

B) -1

Answer

A) -2

Answer

C) 0

Answer

D) +2

Question 9

Which of the following chemical reactions is NOT a redox reaction?

Accepted Answer

B) $AgNO_3(aq) + NaCl(aq) \rightarrow AgCl(s) + NaNO_3(aq)$

Answer

A) $2Na(s) + Cl_2(g) \rightarrow 2NaCl(s)$

Answer

C) $Zn(s) + 2HCl(aq) \rightarrow ZnCl_2(aq) + H_2(g)$

Answer

D) $CH_4(g) + 2O_2(g) \rightarrow CO_2(g) + 2H_2O(g)$

Question 10

What is the oxidation state of sulfur in sulfuric acid ($H_2SO_4$)?

Accepted Answer

C) +6

Answer

A) +2

Answer

B) +4

Answer

D) -2

Question 11

In an electrochemical cell, oxidation always occurs at the:

Accepted Answer

A) Anode

Answer

B) Cathode

Answer

C) Salt bridge

Answer

D) External voltmeter

Question 12

Determine the oxidation number of carbon in methane ($CH_4$).

Accepted Answer

C) -4

Answer

A) +4

Answer

B) +2

Answer

D) 0

Question 13

A reducing agent is defined as a chemical species that:

Accepted Answer

B) Loses electrons and undergoes oxidation

Answer

A) Gains electrons and undergoes reduction

Answer

C) Gains electrons and undergoes oxidation

Answer

D) Loses electrons and undergoes reduction

Question 14

What is the average oxidation state of iron in magnetite ($Fe_3O_4$)?

Accepted Answer

A) $+\frac{8}{3}$

Answer

B) +2

Answer

C) +3

Answer

D) $+\frac{3}{8}$

Question 15

Consider the decomposition reaction: $2H_2O_2(aq) \rightarrow 2H_2O(l) + O_2(g)$

In this reaction, oxygen is:

Accepted Answer

C) Both oxidized and reduced

Answer

A) Oxidized only

Answer

B) Reduced only

Answer

D) Neither oxidized nor reduced

Question 16

The standard electrode potential ($E^\circ$) of the Standard Hydrogen Electrode (SHE) is defined as:

Accepted Answer

A) 0.0 V

Answer

B) +1.0 V

Answer

C) -1.0 V

Answer

D) +0.5 V

Question 17

What is the oxidation state of chlorine in perchloric acid ($HClO_4$)?

Accepted Answer

D) +7

Answer

A) +1

Answer

B) +3

Answer

C) +5

Question 18

Consider the equation: $CuSO_4(aq) + Zn(s) \rightarrow ZnSO_4(aq) + Cu(s)$

This reaction is classified as a:

Accepted Answer

B) Metal displacement reaction

Answer

A) Non-metal displacement reaction

Answer

C) Acid-base neutralization reaction

Answer

D) Thermal decomposition reaction

Question 19

What is the oxidation number of chlorine in elemental chlorine gas ($Cl_2$)?

Accepted Answer

A) 0

Answer

B) -1

Answer

C) +1

Answer

D) +2

Question 20

Consider the redox equation: $Zn(s) + Cu^{2+}(aq) \rightarrow Zn^{2+}(aq) + Cu(s)$

How many electrons are transferred per atom of zinc oxidized in this reaction?

Accepted Answer

B) 2

Answer

A) 1

Answer

C) 3

Answer

D) 4

Set 2Grade 11 : Chemistry - Redox Reactions