Mid sem test

Oxidation reduction

Quiz Type

Practice

Subject

Chemistry

Level

Level 200

Questions

10 questions

Created By

Michael Tetteh

Quick Rules

Time limit: 10 minutes
Multiple attempts are not allowed
All questions must be answered to submit

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Question 1 of 10

Question 1

True false Understanding

Oxidation is the process of gaining electrons.

True

False

Correct

Explanation

Oxidation is defined as the loss of electrons, not the gain. When a substance is oxidized, it increases its oxidation state by losing electrons, which is a fundamental concept in oxidation-reduction (redox) reactions.

Question 2

True false Understanding

Reduction involves the gain of electrons.

True

Correct

False

Explanation

Reduction is defined as the gain of electrons by a substance, resulting in a decrease in oxidation state. This is a core principle in oxidation-reduction (redox) reactions, where one substance is oxidized while another is reduced.

Question 3

True false Understanding

In a redox reaction, both oxidation and reduction occur simultaneously.

True

Correct

False

Explanation

By definition, redox reactions involve simultaneous oxidation and reduction processes. As one substance loses electrons (oxidation), another substance must gain those electrons (reduction), maintaining the balance of charge and mass.

Question 4

Assertion reason Analyzing

Assertion (A): Oxidation-reduction reactions are fundamental processes in chemistry that involve the transfer of electrons between species. Reason (R): Oxidation occurs when a substance loses electrons, while reduction occurs when a substance gains electrons.

Both A and R are true, and R is the correct explanation of A

Correct

Both A and R are true, but R is NOT the explanation of A

A is true but R is false

A is false but R is true

Explanation

Both statements are true. The assertion describes the significance of oxidation-reduction reactions in chemistry, and the reason accurately defines the processes of oxidation and reduction, which underpins the assertion.

Question 5

Basic multiple choice Remembering

What does oxidation refer to in a chemical reaction?

Loss of electrons

Correct

Gain of protons

Gain of electrons

Loss of neutrons

Explanation

Oxidation is defined as the loss of electrons during a chemical reaction, leading to an increase in oxidation state.

Question 6

Basic multiple choice Understanding

In a redox reaction, what role does a reducing agent play?

It donates electrons

Correct

It accepts electrons

It is oxidized

It does not participate in the reaction

Explanation

A reducing agent donates electrons to another substance and is oxidized in the process, facilitating the reduction of that substance.

Question 7

Basic multiple choice Understanding

Which of the following is a characteristic of oxidation?

Increase in oxidation state

Correct

Decrease in mass

Production of energy

Formation of ions only

Explanation

Oxidation is characterized by an increase in oxidation state, reflecting the loss of electrons and the change in charge of the species involved.

Question 8

Basic multiple choice Remembering

What happens to an element that undergoes reduction?

It gains electrons

Correct

It loses electrons

It increases in temperature

It requires oxygen

Explanation

Reduction involves gaining electrons, which decreases the oxidation state of the element in question.

Question 9

Complex multiple choice Understanding

A laboratory experiment requires the reaction of iron with copper sulfate. If iron is oxidized and copper is reduced in this process, which of the following best describes the roles of iron and copper in this redox reaction?

Iron acts as the reducing agent while copper acts as the oxidizing agent.

Correct

Iron acts as the oxidizing agent while copper acts as the reducing agent.

Both iron and copper act as oxidizing agents in the reaction.

Both iron and copper act as reducing agents in the reaction.

Explanation

Iron donates electrons, getting oxidized in the process, thus serving as the reducing agent. Copper, on the other hand, accepts electrons and is reduced, serving as the oxidizing agent. The misconception is that either element can serve both roles simultaneously or incorrectly assigning the oxidation/reduction roles to them.

Question 10

Complex multiple choice Understanding

In an electrochemical cell where zinc is oxidized, and copper ions are reduced, which of the following statements best describes the flow of electrons and the corresponding half-reactions?

Electrons flow from zinc to copper and the half-reactions are Zn → Zn²⁺ + 2e⁻ and Cu²⁺ + 2e⁻ → Cu.

Correct

Electrons flow from copper to zinc and the half-reactions are Cu → Cu²⁺ + 2e⁻ and Zn²⁺ + 2e⁻ → Zn.

Electrons flow from both zinc and copper simultaneously to form a stable reaction.

Zinc and copper do not participate in electron transfer but instead create a chemical equilibrium.

Explanation

In this electrochemical cell, zinc oxidizes and loses electrons, while copper improves and gains electrons. Thus, electrons flow from zinc to copper. The correct half-reactions state that zinc is oxidized to zinc ions while copper ions take on electrons to form copper metal. The distractors represent common misconceptions about electron flow.