MCQs on Oxidation Reduction

Oxidation-Reduction reactions are reactions that involve the transfer of electrons between chemical species. A simple definition of redox reactions considers oxidation as the gain of oxygen atoms and reduction as the loss of oxygen atoms. A redox reaction can also be defined as a reaction in which some of the elements undergo a change in oxidation number. The oxidising agent is by definition the substance containing the atom which shows a decrease in oxidation number. Redox reactions are electron transfers by definition.

1. The total of the oxidation number in an element is

  1. charge
  2. volatility
  3. reduction
  4. oxidation

Answer: (a)

2. The reduction is a gain of

  1. electrons
  2. protons
  3. neutros
  4. oxygen

Answer: (a)

3. Which of the following is not a reducing agent?

  1. CO2
  2. SO2
  3. NO2
  4. ClO2

Answer: (a)

4. A number which is assigned to each atom or ion in a compound which explains its degree of oxidation is called

  1. oxidation state only
  2. oxidation number
  3. oxidation degree only
  4. oxidation state and number

Answer: (d)

5. The gain of oxygen is known as

  1. oxidation
  2. reduction
  3. halogenation
  4. chlorination

Answer: (a)

6. Which of the following undergoes a maximum change in its oxidation number, when a mixture of oxalic acid, potassium chlorate and sulphuric acid is heated?

  1. S
  2. Cl
  3. H
  4. C

Answer: (b)

7. The oxidation number for oxygen will always be

  1. 2
  2. -2
  3. 1
  4. -1

Answer: (b)

8. The reduction is the decrease in

  1. oxidation number
  2. charge
  3. solubility
  4. none of the above

Answer: (a)

9. The reaction in which oxidation and reduction takes place at the same time is called

  1. redox reaction
  2. oxidation reaction
  3. reduction reaction
  4. none of the above

Answer: (a)

10. Hydrogen (H2) is used for making

  1. margarine only
  2. ammonia only
  3. salts
  4. margarine and ammonia

Answer: (d)

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