Redox reactions which stands for reduction-oxidation reactions, is a crucial component of chemistry education. They involve the transfer of electrons between chemical species, resulting in a change in the oxidation states and the transformation of substances. In this article, we have curated a diverse set of MCQs for Class 11 Chemistry Chapter – 7 to help students test and enhance their understanding of redox reactions.
Class 11 Chemistry Redox Reactions MCQs with Answer
Q1. When magnesium and iron react with steam, they produce:
- H2
- O2
- CO2
- None of these.
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Ans: 1.H2
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Q.3. The oxidation number of an element in a compound is evaluated on the basis of certain rules. Which of the
following rules is not correct in this respect?
- The oxidation number of hydrogen is always +1.
- The algebraic sum of all the oxidation numbers in a compound is zero.
- An element in the free or the uncombined state bears oxidation number zero.
- In all its compounds, the oxidation number of fluorine is – 1.
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Ans: 1. The oxidation number of hydrogen is always +1.
Explanation:
In ionic hydrides hydrogen exist in -1 oxidation state because the hydrogen acquires negative charge in the presence of its companion.
Q7. Which are of the following can act as oxidising as well reducing agent?
- H2
- I2
- H2O2
- All of these
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Ans: 4. All of these
Explanation:
All of them can act as oxidising as well as reducing agent because their oxidation state can increase as well as decrease
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Ans: 2. Stronger reducing agent than H+ / H, couple.
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Q14. In the following reaction,
2Mg(s) + O2 (g) → 2Mgo(s)
with respect to Mg, the process is called:
- Oxidation.
- Reduction.
- Redox reaction.
- None of these.
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Ans: 1. Oxidation.
Q15. From the given species such as Li, K, Ca and Na, which of the following is the strongest reducing agent?
- Na
- Li
- Ca
- K
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Ans: 2. Li
Q16. Water molecule is formed by the reaction,
2H2 + O2 → 2H2 O
What does happen in this reaction?
- Electrons are transferred from H to O-atom.
- Electrons are transferred from 0 to H-atom.
- Electrons are accepted by H from O-atom.
- Electrons are donated by O to H-atom.
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Ans: 1. Electrons are transferred from H to O-atom.
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Ans: 4. Both (a) and (c)
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Ans: 1. Oxidising agent.
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Ans: 4. Chromium being reduced.
Q20. Number of moles of MnO–4required to oxidise one mole of ferrous oxalate completely in an acidic medium will be:
- 0.6 moles.
- 0.4 moles.
- 7.5 moles.
- 0.2 moles.
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Ans: 1. 0.6 moles.
Q21. If a reaction is carried out in acidic medium then which is used to balance the equation?
- H+ ions.
- OH– ions.
- H– ions.
- O2- ions.
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Ans: 1.H+ ions.
Q22.
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Q23
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Ans: 2. Canode to cathode.
Explanation:
In Daniell cell, electrons flow from anode to cathode and current flows from cathode to anode.
Q24. To balance the charges which of the following is added to one side of the half-reaction?
- Proton.
- Hydrogen.
- Oxygen.
- Electrons.
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Ans: 4. Electrons.
Explanation:
Electrons are added to one side of the half-reaction to balance the charge.
Q25. To balance the charges which of the following is added to one side of the half-reaction?
- Proton.
- Hydrogen.
- Oxygen.
- Electrons.
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Ans: 4. Electrons.
Explanation:
Electrons are added to one side of the half-reaction to balance the charge
Q26. Which of the following processes takes place in oxidation?
- Addition of oxygen.
- Addition of hydrogen.
- Removal of oxygen.
- Removal of chlorine.
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Ans: 1. Addition of oxygen.
Explanation:
Addition of oxygen takes place in oxidation.
Q27. Which of the following processes does not involve oxidation of iron?
- Rusting of iron sheets.
- Decolourisation of blue CuSO4 solution by Fe.
- Formation of Fe(CO)5 from Fe.
- Liberation of H2 from steam by iron at high temperature.
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Ans: 3. Formation of Fe(CO)5 from Fe.
Q28. In the reaction between copper nitrate solution and zinc, copper ions are reduced by gaining electrons from:
- Copper.
- Nitrogen.
- Zinc.
- Oxygen.
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Ans: 3. Zinc.
Q29. An element if present in the free or the uncombined state, its each atom bears an oxidation number:
- More than 1
- Less than 1
- More than 2
- Zero.
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Ans: 4. Zero.
Q30. Which of the following reactions represent(s) redox process?
- Electrochemical process for extraction of highly reactive metals and non-metals.
- Manufacturing of caustic soda.
- Corrosion of metals.
- All of the above.
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Ans: 4. All of the above.
Explanation:
Electrochemical processes for the extraction of highly reactive metals and non-metals, manufacturing of chemical compounds like
caustic soda, operation of dry and wet batteries and corrosion of metals fall within the range of redox processes.