Redox Reactions Quiz

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  • 1/10 Questions

    What is a reducing agent?

    • It undergoes reduction
    • It undergoes chemical changes
    • It undergoes oxidation
    • It undergoes no changes
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About This Quiz

Check out the fantastic quiz on redox reactions with questions and answers. With this quiz, you'd be able to evaluate your knowledge of inorganic chemistry and chemical reactions. You must know that an oxidation-reduction (commonly known as redox) reaction involves the transfer of electrons between two chemical species. In this chemical reaction, one species undergoes oxidation, whereas another one goes into a reduction state. Do you think you can solve this test easily? If yes, take up the quiz now.

Redox Reactions Quiz - Quiz

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  • 2. 

    What is the oxidation number of Fe in FeO?

    • -2

    • 2-

    • +2

    • 2+

    Correct Answer
    A. +2
    Explanation
    The oxidation number of Fe in FeO is +2. In FeO, oxygen always has an oxidation number of -2. Since the overall charge of FeO is neutral, the sum of the oxidation numbers of Fe and O must equal zero. Therefore, the oxidation number of Fe can be calculated as +2 to balance out the -2 oxidation number of O.

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  • 3. 

    Balance this half equation: Cu2+ (aq) --->  Cu (s)

    • Cu2+ (s) --->  Cu (aq)

    • Cu2+ (aq) --->  Cu (s)  +2e

    • Cu2+ (aq) + 2e --->  Cu (s)  

    • Cu2+ (aq) + 3e --->  Cu (s)

    Correct Answer
    A. Cu2+ (aq) + 2e --->  Cu (s)  
    Explanation
    The correct answer is Cu2+ (aq) + 2e ---> Cu (s). This is the correct answer because in the half equation, Cu2+ (aq) is being reduced to Cu (s) by gaining 2 electrons. The balanced equation shows the transfer of 2 electrons from the Cu2+ ion to form solid Cu.

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  • 4. 

    What is the oxidation number in of Phosphorus in Na3PO4Na3PO4?

    • +5

    • -5

    • +4

    • -4

    Correct Answer
    A. +5
    Explanation
    The oxidation number of an element refers to the charge that element would have if all the bonds in the compound were ionic. In the case of Na3PO4, sodium (Na) has a charge of +1, and there are three sodium atoms. Oxygen (O) usually has a charge of -2, and there are four oxygen atoms. Therefore, the total charge from sodium and oxygen is +3 and -8 respectively. Since the compound is neutral, the total charge must be zero. This means that the oxidation number of phosphorus (P) must be +5 to balance out the charges and make the compound neutral.

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  • 5. 

    How does hydrogen act as a reducing agent?

    • By taking oxygen only

    • By taking hydrogen only

    • By giving electrons only

    • By taking oxygen and giving electrons

    Correct Answer
    A. By taking oxygen and giving electrons
    Explanation
    Hydrogen acts as a reducing agent by taking oxygen and giving electrons. In a redox reaction, a reducing agent donates electrons to another species, causing it to be reduced. Hydrogen, being a highly electronegative element, has a strong tendency to attract electrons. Therefore, it can take oxygen from another species and simultaneously donate electrons to it, resulting in the reduction of the other species. This process allows hydrogen to act as a reducing agent.

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  • 6. 

    What are electron-accepting species called?

    • Oxidizing agents

    • Reducing agents

    • Electron acceptors

    • Both a and b

    Correct Answer
    A. Oxidizing agents
    Explanation
    Electron-accepting species are called oxidizing agents because they have the ability to accept electrons from other species during a chemical reaction. This process is known as oxidation, where the oxidizing agent itself gets reduced by gaining electrons. Therefore, oxidizing agents are substances that facilitate the oxidation of other species by accepting electrons.

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  • 7. 

    What is the oxidation state of a pure element?

    • Zero

    • -1

    • +1

    • Depends on the element

    Correct Answer
    A. Zero
    Explanation
    The oxidation state of a pure element is zero because in a pure element, all the atoms have an equal number of protons and electrons. Since oxidation state is a measure of the number of electrons gained or lost by an atom in a compound, a pure element does not gain or lose any electrons and therefore has an oxidation state of zero.

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  • 8. 

    If an element is in its highest possible oxidation state in a compound. It can function as ____________.

    • A powerful reducing agent

    • A powerful oxidising agent

    • A lower reducing agent

    • None of above

    Correct Answer
    A. A powerful oxidising agent
    Explanation
    When an element is in its highest possible oxidation state in a compound, it means that it has lost or donated all of its electrons. This results in a high positive charge on the element, making it highly electronegative and capable of attracting electrons from other elements. Therefore, it can function as a powerful oxidizing agent, as it has a strong ability to accept electrons and cause other elements to undergo oxidation.

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  • 9. 

    Which one of the following does not an oxidizing agent include?

    • Potassium iodide

    • Bromine solutions

    • Potassium magnate

    • Potassium dichromate

    Correct Answer
    A. Potassium iodide
    Explanation
    Potassium iodide does not include an oxidizing agent because it is a reducing agent. In chemical reactions, oxidizing agents gain electrons and are reduced, while reducing agents lose electrons and are oxidized. Potassium iodide is commonly used as a reducing agent, as it readily donates its electrons to other substances. Therefore, it cannot act as an oxidizing agent.

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  • 10. 

    Which one is not a redox reaction?

    • H2 + Cl2 → 2HClC+O2→CO2

    • Na2CO3 → Na2O + CO2

    • CaCO3 → CaO + CO2

    • 2NaH → 2Na + H2

    Correct Answer
    A. CaCO3 → CaO + CO2
    Explanation
    The reaction CaCO3 → CaO + CO2 is not a redox reaction because there is no change in the oxidation states of the elements involved. In a redox reaction, there is a transfer of electrons between the reactants, resulting in a change in their oxidation states. In this reaction, calcium carbonate (CaCO3) is simply decomposing into calcium oxide (CaO) and carbon dioxide (CO2), without any change in oxidation states.

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  • Current Version
  • Aug 08, 2023
    Quiz Edited by
    ProProfs Editorial Team
  • Feb 16, 2022
    Quiz Created by
    Catherine Halcomb
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