This set of Class 11 Chemistry Chapter 8 Multiple Choice Questions & Answers (MCQs) focuses on “Redox Reactions in Terms of Electron Transfer Reactions”.
1. What is the oxidation half reaction of Cu+2 + Zn → Cu + Zn+2?
a) Zn → Zn+2
b) Cu+2 → Cu
c) Cu+2 → Zn+2
d) Zn → Cu
View Answer
Explanation: Oxidation is the loss of electrons by an atom, ion or molecule. It is also known as de-electronation. Here in the above given chemical reaction Cu+2 + Zn → Cu + Zn+2, the oxidation half-reaction is Zn → Zn+2.
2. When a zinc rod is kept in a copper nitrate solution what happens?
a) zinc is deposited on copper
b) copper is deposited on zinc
c) zinc is deposited in the beaker
d) copper is deposited in the beaker
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Explanation: When zinc is placed in copper nitrate solution the intensity of the blue colour is produced and copper iron is deposited on zinc. This is a Redox reaction between zinc and an aqueous solution of copper nitrate occurring in a beaker.
3. In this reaction Cu+2 + Zn → Cu + Zn+2, what is an oxidising agent?
a) copper
b) zinc
c) hydrogen
d) oxygen
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Explanation: Oxidant or oxidizing agent is a chemical substance which can accept one or more electrons and causes oxidation of some other species. Here to accept electrons from zinc, so copper is an oxidizing agent.
4. Loss of electrons is _________________
a) oxidising agent
b) oxidation
c) reducing agent
d) reduction
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Explanation: Oxidizing agent is the acceptor of electrons and the reducing agent is a donor of the electrons, where oxidation is termed by loss of electrons by any species and reduction is gain of electrons by any species.
5. Intensity of blue colour increases gradually when _________________
a) copper rod is dipped in silver nitrate solution
b) silver rod is dipped in copper nitrate solution
c) zinc rod is dipped in silver solution
d) copper rod is dipped in zinc rod solution
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Explanation: When a copper rod is dipped in silver nitrate solution, a redox reaction occurs between Copper and an aqueous solution of silver nitrate. So the intensity of blue colour increases gradually as silver deposits on the rod.
6. Which of the following is true as per metal activity series?
a) Zn<Ag<Cu
b) Zn<Cu<Ag
c) Zn>Ag>Cu
d) Zn>Cu>Ag
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Explanation: Metal activity series or electrochemical series is a series in the decreasing order of metals which are active during a chemical reaction comparatively with each other. Here, Zinc’s activity is greater than Copper’s activity and Copper’s activity is greater than that of silver.
7. What is a reducing agent of the reaction Cu+2 + Zn → Cu + Zn+2?
a) copper
b) zinc
c) hydrogen
d) oxygen
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Explanation: Reductant or reducing agent is a chemical substance which can give one or more electrons and causes reduction of some other species in a chemical reaction. Therefore, zinc is a reducing agent in this reaction.
8. The oxidation number of oxidant increases in a Redox reaction.
a) true
b) false
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Explanation: Oxidising agent is also known as an oxidant, the oxidation number of an oxidant decreases in a Redox reaction whereas the oxidation number of reductant increases in a reaction. Reducing agent is known as a reductant.
9. Which of the following is not an oxidising agent?
a) magnesium oxide
b) carbon dioxide
c) ozone
d) sodium hydride
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Explanation: Molecules of most electronegative elements, compounds having an element in the highest oxidation state and oxides of metals and nonmetals are examples of oxidising agents. But sodium hydride is a metallic hydride, so it is not an oxidizing agent.
10. Hydrogen peroxide is a ______________
a) oxidising agent
b) reducing agent
c) both reducing and oxidizing agent
d) neither reducing nor an oxidizing agent
View Answer
Explanation: Hydrogen peroxide, which is chemically written as H2O2, is a strong oxidizer as well a reducer. As it contains two hydrogens and to oxygens, it easily looses hydrogen or oxygen i.e. oxidizes and reduces respectively.
Sanfoundry Global Education & Learning Series – Chemistry – Class 11.
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