Redox reaction

Quiz Type

Practice

Subject

Chemistry

Level

Level 100

Questions

10 questions

Created By

Lordina Atta-effah

Quick Rules

Time limit: 50 minutes
Multiple attempts are not allowed
All questions must be answered to submit

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Question 1 of 10

Question 1

Basic multiple choice Remembering

What is a redox reaction?

A reaction involving the transfer of electrons

Correct

A reaction that only involves the transfer of protons

A reaction where no energy changes occur

A reaction that does not involve any bonds

Explanation

A redox reaction is characterized by the transfer of electrons between substances. This involves oxidation (loss of electrons) and reduction (gain of electrons).

Question 2

Basic multiple choice Remembering

In a redox reaction, what happens to the substance that is oxidized?

It gains electrons

It loses electrons

Correct

It remains unchanged

It becomes a reactant

Explanation

The substance that is oxidized in a redox reaction loses electrons, leading to an increase in its oxidation state.

Question 3

Basic multiple choice Understanding

What does the term 'reduction' refer to in a redox reaction?

Loss of electrons

Gain of electrons

Correct

Formation of new compounds

Increase in temperature

Explanation

Reduction refers to the process where a substance gains electrons, which decreases its oxidation state.

Question 4

Basic multiple choice Remembering

In a redox reaction, the substance that is reduced is often called what?

Oxidizing agent

Correct

Reducing agent

Reactant

Product

Explanation

The substance that is reduced (gains electrons) in a redox reaction is called the oxidizing agent, as it facilitates oxidation of another substance.

Question 5

Basic multiple choice Understanding

What role does an oxidizing agent play in a redox reaction?

It donates electrons

It accepts electrons

Correct

It combines with water

It releases energy

Explanation

An oxidizing agent gains electrons during the reaction, allowing it to oxidize another substance while being reduced itself.

Question 6

Complex multiple choice Understanding

A redox reaction involves the transfer of electrons between two species. If a metal oxide is reduced to its corresponding metal while another metal ion is oxidized to its corresponding metal oxide, which of the following statements correctly identifies the oxidizing and reducing agents in this reaction?

The metal oxide is the reducing agent and the metal ion is the oxidizing agent.

Correct

The metal ion is the reducing agent and the metal oxide is the oxidizing agent.

Both the metal oxide and the metal ion act as reducing agents.

The metal ion does not play a role in the redox reaction.

Explanation

In a redox reaction, the substance that loses electrons is oxidized and acts as the reducing agent, while the substance that gains electrons is reduced and acts as the oxidizing agent. Here, the metal oxide is reduced to the metal (gaining electrons), making it the reducing agent, while the metal ion that is oxidized loses electrons and acts as the oxidizing agent.

Question 7

Complex multiple choice Analyzing

Consider a redox reaction occurring in an electrochemical cell where a copper ion (Cu²⁺) is reduced to copper metal (Cu) and zinc metal (Zn) is oxidized to zinc ion (Zn²⁺). If the electrode reactions are reversed, what would be the effect on the overall cell reaction?

The overall cell potential will remain the same, with no impact on the reaction direction.

The cell reaction will proceed in the same direction, maintaining the flow of electrons.

The overall cell potential will reverse, leading to a spontaneous reaction in the opposite direction.

Correct

The reaction will cease, as reversing the electrodes stops all activity in the electrochemical cell.

Explanation

Reversing the electrode reactions in an electrochemical cell changes the direction of the electron flow and the overall cell potential. The reduction and oxidation reactions will switch roles, affecting the spontaneity and direction of the overall cell reaction. Only by understanding this relationship can one predict the outcomes of such a switch effectively.

Question 8

Case based multiple choice Understanding

[Case Scenario] A chemistry lab is conducting experiments to observe redox reactions. In one experiment, a student mixes iron(III) chloride (FeCl₃) with zinc metal (Zn) and notes several observations: a color change in the solution from yellow to reddish, bubbling gases, and the formation of a metallic deposit at the bottom. Based on these observations, what can be inferred about the nature of the reaction occurring? Question: What does this experimental setup primarily demonstrate about the redox reaction taking place?

Iron is being reduced, while zinc is oxidized.

Correct

Zinc is being reduced, while iron is oxidized.

No electron transfer is happening, only a physical change occurs.

Both iron and zinc are in their elemental forms and do not react with each other.

Explanation

The reaction demonstrates that zinc is more reactive than iron and thus can displace iron from iron(III) chloride. This illustrates the principles of oxidation and reduction in redox reactions.

Question 9

Case based multiple choice Understanding

[Case Scenario] During a series of experiments aimed at demonstrating redox reactions, a team of students conducted an experiment combining potassium permanganate (KMnO₄) and sodium bisulfite (NaHSO₃). They noted that the initially deep purple solution of potassium permanganate gradually turned colorless after the addition of sodium bisulfite. The students concluded that the purple color disappearing was an indication of a redox reaction taking place. Question: What explanation best describes the color change observed in this redox reaction?

Potassium permanganate is being reduced as it gains electrons and loses its color.

Correct

Sodium bisulfite is oxidized, leading to the enhancement of the permanganate's purple color.

Temperature changes caused by the reaction are responsible for the color change.

Both potassium permanganate and sodium bisulfite are oxidized simultaneously, resulting in color loss.

Explanation

In this redox reaction, potassium permanganate (KMnO₄) acts as an oxidizing agent and is reduced, leading to the color change from purple to colorless as it gains electrons and forms manganese(II) ions.

Question 10

Case based multiple choice Understanding

[Case Scenario] A researcher is looking to understand the reactivity of various metal oxides in redox reactions. They choose to test the behavior of lead(II) oxide (PbO) and copper(II) oxide (CuO) when placed in a reducing environment with hydrogen gas (H₂). After conducting the experiment, they observe that both oxides are reduced to their respective metals, lead (Pb) and copper (Cu). Question: Based on the results, what can be concluded about the relative strengths of lead(II) oxide and copper(II) oxide as oxidizing agents?

Lead(II) oxide is a stronger oxidizing agent than copper(II) oxide.

Correct

Copper(II) oxide is a stronger oxidizing agent than lead(II) oxide.

Both lead(II) oxide and copper(II) oxide exhibit the same strength as oxidizing agents.

Neither lead(II) oxide nor copper(II) oxide acts as oxidizing agents in this reaction.

Explanation

Lead(II) oxide is shown to be a stronger oxidizing agent than copper(II) oxide in this experiment, as it was effectively reduced by hydrogen, suggesting it has a greater ability to accept electrons.