Oxidation and Reduction Practice Questions
SPM (Malaysia) · SPM Chemistry · 144 free MCQs with instant results and detailed explanations.
144
Total
41
Easy
70
Medium
33
Hard
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Sample Questions from Oxidation and Reduction
Here are 10 sample questions. Start a quiz to get randomized questions with scoring.
Q1
Easy
Which of the following processes involves oxidation?
A.
The reaction of iron with oxygen to form rust
B.
The reaction of hydrogen with oxygen to form water
C.
The reduction of copper(II) ions to copper metal
D.
The conversion of glucose to lactic acid
Show Answer & Explanation
Correct Answer: A
Rust formation occurs when iron reacts with oxygen, resulting in the loss of electrons by iron, which constitutes oxidation.
Q2
Easy
In a redox reaction, if substance A is oxidized, what is the role of substance A?
A.
Oxidizing agent
B.
Reducing agent
C.
Neutral agent
D.
Catalyst
Show Answer & Explanation
Correct Answer: B
When substance A is oxidized, it loses electrons and thereby facilitates the reduction of another substance; hence, it acts as a reducing agent.
Q3
Easy
Which of the following statements about reduction is true?
A.
Reduction involves the gain of electrons.
B.
Reduction results in the increase of oxidation number.
C.
Reduction can occur without oxidation.
D.
Reduction does not affect the charge of atoms.
Show Answer & Explanation
Correct Answer: A
Reduction is defined as the process of gaining electrons, which decreases the oxidation number of the substance involved.
Q4
Medium
Which of the following represents a reduction process in a redox reaction?
A.
Loss of electrons
B.
Gain of oxygen
C.
Gain of electrons
D.
Loss of hydrogen
Show Answer & Explanation
Correct Answer: C
Reduction is defined as the gain of electrons by an atom or molecule. Therefore, option C accurately represents a reduction process.
Q5
Medium
In the reaction 2Mg + O2 ā 2MgO, which species is oxidized?
A.
Mg
B.
O2
C.
MgO
D.
No oxidation occurs
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Correct Answer: A
Magnesium (Mg) loses electrons to form MgO, which means it undergoes oxidation. Hence, Mg is the species that is oxidized.
Q6
Medium
Which of the following compounds can act as a reducing agent?
A.
H2O2
B.
NaCl
C.
C6H12O6
D.
Fe2O3
Show Answer & Explanation
Correct Answer: C
Glucose (C6H12O6) can donate electrons in certain chemical reactions, thereby acting as a reducing agent. The other options do not have this capability.
Q7
Medium
What is the main characteristic of a redox reaction?
A.
It involves the transfer of protons.
B.
It involves the transfer of electrons.
C.
It occurs only in acids.
D.
It produces heat only.
Show Answer & Explanation
Correct Answer: B
Redox reactions fundamentally involve the transfer of electrons between species, which defines the oxidation and reduction processes occurring.
Q8
Hard
In a certain redox reaction, zinc is oxidized while copper ions are reduced. Which of the following statements correctly identifies the oxidation and reduction processes in this reaction?
A.
Zinc loses electrons and copper gains electrons.
B.
Zinc gains electrons and copper loses electrons.
C.
Zinc remains neutral while copper is oxidized.
D.
Zinc is reduced while copper is oxidized.
Show Answer & Explanation
Correct Answer: A
In a redox reaction, oxidation refers to the loss of electrons and reduction refers to the gain of electrons. Zinc, being oxidized, loses electrons, while copper ions, being reduced, gain those electrons.
Q9
Hard
Consider the redox reaction where 2Fe^3+ + Zn ā 2Fe^2+ + Zn^2+. What is the standard reduction potential (EĀ°) for this reaction if EĀ° for Fe^3+/Fe^2+ is +0.77 V and EĀ° for Zn^2+/Zn is -0.76 V?
A.
+1.53 V
B.
+0.01 V
C.
+0.23 V
D.
-1.53 V
Show Answer & Explanation
Correct Answer: A
To find the standard reduction potential for the overall reaction, sum the reduction potential for Fe^3+/Fe^2+ and the oxidation potential for Zn/Zn^2+. Thus, +0.77 V + 0.76 V = +1.53 V.
Q10
Hard
In a redox reaction between potassium permanganate (KMnO4) and hydrogen peroxide (H2O2) in acidic medium, what is the oxidation state of manganese after the reaction?
A.
+4
B.
+2
C.
+7
D.
+6
Show Answer & Explanation
Correct Answer: B
In the reaction, KMnO4 is reduced and the oxidation state of manganese changes from +7 to +2. Therefore, the correct answer is +2.
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Oxidation and Reduction ā SPM (Malaysia) SPM Chemistry Practice Questions Online
This page contains 144 practice MCQs for the chapter Oxidation and Reduction in SPM (Malaysia) SPM Chemistry. The questions are organized by difficulty ā 41 easy, 70 medium, 33 hard ā so you can choose the right level for your preparation.
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