Redox Reactions Multiple Choice Questions

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Redox Reactions Multiple Choice Questions

Question 1. A compound contains elements X, Y, and Z with oxidation numbers +3, +5, and -2 respectively. The possible formula of a compound containing these elements is

  1. XYZ2
  2. Y2(XZ3)2
  3. X3(YZ4)3
  4. X3(Y4Z)2

Answer: 3. X3(YZ4)3

Question 2. In which of these compounds does chlorine display a positive oxidation number?

  1. HC1
  2. HOC1
  3. BrCl3
  4. NaC1

Answer: 2. HOC1

Question 3. If a metal cation M3+ gains three electrons its oxidation number will become

  1. +6
  2. -3
  3. 0
  4. +3

Answer: 3. 0

Question 4. In which of the following compounds does Cr display the highest oxidation state?

  1. Cr203
  2. CrCl3
  3. Cr(OH)2
  4. K2Cr04

Answer: 4. K2Cr04

Question 5. Which of the following will reduce Ag+ to Ag but not Niz+ to Ni?

  1. Fe
  2. Fb
  3. Be
  4. Zn

Answer: 2. Fb

Question 6. The oxidized form of MnOz is

  1. Mn2+
  2. MnO-4
  3. MnO-4
  4. Mn(OH)4

Answer: 2. MnO-4

Question 7. Which of these is a redox reaction?

\(\mathrm{NaOH}+\mathrm{HCl} \longrightarrow \mathrm{NaCl}+\mathrm{H}_2 \mathrm{O}\) \(\mathrm{AgNO}_3+\mathrm{NaCl} \longrightarrow \mathrm{AgCl}+\mathrm{NaNO}_3\) \(\mathrm{Zn}+\mathrm{H}_2 \mathrm{SO}_4 \longrightarrow \mathrm{ZnSO}_4+\mathrm{H}_2\) \(\mathrm{FeSO}_4+2 \mathrm{H}_2 \mathrm{O} \longrightarrow \mathrm{Fe}(\mathrm{OH})_2+\mathrm{H}_2 \mathrm{SO}_4\)

Answer: 3. \(\mathrm{Zn}+\mathrm{H}_2 \mathrm{SO}_4 \longrightarrow \mathrm{ZnSO}_4+\mathrm{H}_2\)

Question 8. In which of these compounds does carbon have a negative oxidation number?

  1. CH4
  2. CH2C12
  3. CC14
  4. HCHO

Answer: 1. CH4

Question 9. Consider the reaction

⇒ \(\mathrm{Zn}+\mathrm{Cu}^{2+} \longrightarrow \mathrm{Zn}^{2+}+\mathrm{Cu}\)

Which of the following is the correct statement?

  1. Zn is reduced to Zn2+
  2. Cu2+ is oxidized to Cu.
  3. Zn is oxidized to Zn2+
  4. Zn is the oxidizing agent

Answer: 3. Zn is oxidized to Zn2+

Question 10. What is the oxidation state of N in Mg3N2?

⇒ \(\mathrm{NaClO}_3 \longrightarrow \mathrm{NaClO}+2 \mathrm{NaCl}\)

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

Answer: 1. -3

Question 11. In the following reaction which element loses as well as gains electrons?

⇒ \(\mathrm{NaClO}_3 \longrightarrow \mathrm{NaClO}+2 \mathrm{NaCl}\)

  1. Na
  2. Cl
  3. O
  4. The reaction is Not Feasible.

Answer:

Question 12. In the redox reaction shown here, what are the coefficients x and y?

⇒ \(y \mathrm{SnCl}_2+x \mathrm{FeCl}_3 \longrightarrow y \mathrm{SnCl}_4+x \mathrm{FeCl}_2\)

  1. 2,1
  2. 1,1
  3. 1,3
  4. 1,2

Answer: 1. 2,1

Question 13. What is the value of x in the following half-reaction?

⇒ \(\mathrm{C}_2 \mathrm{O}_7^{2-}+4 \mathrm{H}^{+}+x \mathrm{e}^{-} \longrightarrow 2 \mathrm{Cr}^{3+}+7 \mathrm{H}_2 \mathrm{O}\)

  1. 6
  2. 5
  3. 2
  4. 4

Answer: 1. 6

Question 14. The oxidation number of Os in 0s04 is

  1. +4
  2. +6
  3. +2
  4. +8

Answer: 4. +8

Question 15. Which of these is a disproportionation reaction?

  1. \(2 \mathrm{CuCl} \longrightarrow \mathrm{CuCl}_2+\mathrm{Cu}\)
  2. \(\mathrm{CaCO}_3 \longrightarrow \mathrm{CaO}+\mathrm{CO}_2\)
  3. \(2 \mathrm{~Pb}\left(\mathrm{NO}_3\right)_2 \rightarrow \mathrm{PbO}+4 \mathrm{NO}_2+\mathrm{O}_2\)
  4. \(\mathrm{PCl}_5 \rightarrow \mathrm{PCl}_3+\mathrm{Cl}_2\)

Answer: 1. \(2 \mathrm{CuCl} \longrightarrow \mathrm{CuCl}_2+\mathrm{Cu}\)

Question 16. The oxidation number of Fe in Fe304 is

  1. \(-\frac{8}{3}\)
  2. \(+\frac{8}{3}\)
  3. \(-\frac{2}{3}\)
  4. \(+\frac{2}{3}\)

Answer: 2. \(+\frac{8}{3}\)

Question 17. Which of the following gases is not a reducing agent?

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

Answer: 3. CO2

Question 18. Which of these would be an alternative for A in the given reaction?

⇒ \(2 \mathrm{H}_2 \mathrm{~S}+\mathrm{SO}_2 \longrightarrow 2 \mathrm{H}_2 \mathrm{O}+\mathrm{A}\)

  1. S
  2. SO3
  3. H2SO3
  4. H2SO4

Answer: 1. S

Question 19. Which is the oxidizing agent in the given reaction?

⇒ \(\mathrm{Cl}_2+2 \mathrm{Br}^{-} \longrightarrow \mathrm{Br}_2+2 \mathrm{Cl}^{-}\)

  1. Br-
  2. Cl2
  3. Br2
  4. Cl-

Answer: 2. Cl2

Question 20. When a Cu rod is dipped in a beaker containing an AgNO solution, what change occurs in the tire color of the solution?

  1. Terms
  2. Turns blue
  3. No change
  4. Turns black

Answer: 1. Turms

Question 21. The reaction \(3 \mathrm{ClO}^{-} \longrightarrow \mathrm{ClO}_3^{-}+2 \mathrm{Cl}^{-}\) is an example of

  1. Oxidation
  2. Reduction
  3. Displacement
  4. Disproportionation

Answer: 4. Disproportionation

Question 22. The oxidation number of N in NH is

  1. 0
  2. -3
  3. +1
  4. +3

Answer: 4. +3

Question 23. Which of the following is not possible?

  1. Keeping a zinc sulfate solution in a copper vessel
  2. Keeping a zinc sulfate solution in a silver vessel
  3. Keeping a copper sulfate solution in a zinc vessel
  4. Keeping a copper sulfate solution in a silver vessel

Answer: 3. Keeping a copper sulfate solution in a zinc vessel

Question 24. In which of these compounds does S show the highest oxidation state?

  1. H2S03
  2. H2S04
  3. H2S
  4. SO2

Answer: 2. H2S04

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