Redox Reactions Class 11 Chemistry MCQs

1 Identify disproportionation reaction

A CH4 + 2O2→ CO2 + 2H2O

B CH4 + 4Cl2→ CCl4 + 4HCl

C 2F2 + 2OH-→ 2F- + OF2 + H2O

D 2NO2 + 2OH–→ NO2- + NO3- + H2O

Answer:2NO2 + 2OH–→ NO2- + NO3- + H2O

2 The largest oxidation number exhibited by an element depends on its outer electronic configuration. With which of the following outer electronic configurations the element will exhibit the largest oxidation number?

A 3d1 4s2

B 3d3 4s2

C 3d5 4s1

D 3d5 4s2

View Answer

Answer:3d5 4s2

3 Which of the following arrangements represent increasing oxidation number of the central atom?

A CrO^2- , CIO^-3, CrO2^-4 , MnO^-4

B CIO^-3, CrO2^-4 , MnO^-4 , CrO^-2

C CrO2⁺⁴ , MnO^-4 , CrO^-2 , CIO^3-

D CrO2^4-, MnO^4- , CrO^2- , CIO^3-

View Answer

Answer:CrO^2- , CIO^-3, CrO2^-4 , MnO^-4

4 In which of the following compounds, an element exhibits two different oxidation states.

A NH₂OH7

B NH₄NO₃

C N₂H₄

D N3H

View Answer

Answer:NH₄NO₃

5 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?

A The oxidation number of hydrogen is always +1.

B The algebraic sum of all the oxidation numbers in a compound is zero.

C An element in the free or the uncombined state bears oxidation number zero.

D In all its compounds, the oxidation number of fluorine is – 1

View Answer

Answer:The oxidation number of hydrogen is always +1.

6 Thiosulphate reacts differently with iodine and bromine in the reactions given below:

2S2O3^2- + I² → S4O6^2- + 2I^–

S2O3^2-+ 2Br²⁺ 5H2O → 2SO4^2- + 2Br^–+ 10 H⁺

Which of the following statements justifies the above dual behaviour of thiosulphate?

A Bromine is a stronger oxidant than iodine.

B Bromine is a weaker oxidant than iodine.

C Thiosulphate undergoes oxidation by bromine and reduction by iodine in these reactions.

D Bromine undergoes oxidation and iodine undergoes a reduction in these reactions.

View Answer

Answer:Bromine is a stronger oxidant than iodine.

7 Using the standard electrode potential, find out the pair between which redox reaction is not feasible.

E°Values: Fe3+/ Fe2+ = +0.77; I2/I- = +0.54;

Cu2+/ Cu = -0.34; Ag+ /Ag = + 0.80 V

A Fe3+ and I-

B Ag+ and Cu

C Fe3+ and Cu

D Ag and Fe3+

View Answer

Answer:Ag and Fe3+

8 Eᶱvalues of some redox couples is given below. Based on these values

choose the correct option.

Eᶱ values : Br2/Br–= + 1.90; Ag+/Ag(s) = + 0.80

Cu2+/Cu(s) = + 0.34; I2(s)/I– = + 0.54

A Cu will reduce Br–

B Cu will reduce Ag

C Cu will reduce I–

D Cu will reduce Br2

View Answer

Answer:Cu will reduce Br2

9 The more positive the value of Eᶱ, the greater is the tendency of the species to get reduced. Using the standard electrode potential of redox couples given below to find out which of the following is the strongest oxidising agent. Eᶱ Values : Fe3+/Fe2+ = + 0.77; I2(s)/I– = + 0.54;

Cu2+/Cu = + 0.34; Ag+/Ag = + 0.80V

A Fe3+

B I2(s)

C Cu2+

D Ag

View Answer

Answer:Ag

10 Which of the following is not an example of redox reaction?

A CuO + H2→ Cu + H2O

B Fe2O3 + 3CO → 2Fe + 3CO2

C 2K + F2→ 2KF

D BaCl2 + H2SO4→ BaSO4 + 2HCl

View Answer

Answer:BaCl2 + H2SO4→ BaSO4 + 2HCl

11 he 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?

A The oxidation number of hydrogen is always +1.

B The algebraic sum of all the oxidation numbers in a compound is zero.

C An element in the free or the uncombined state bears oxidation number zero.

D In all its compounds, the oxidation number of fluorine is -1.

View Answer

Answer:The oxidation number of hydrogen is always +1.

12 In which of the following compounds, an element exhibits two different oxidation states.

A NH₂OH

B NH₄NO₃

C N₂H₄

D N₃H

View Answer

Answer:NH₄NO₃

13 The largest oxidation number exhibited by an element depends on its outer electronic configuration. With which of the following outer electronic configurations the element will exhibit largest oxidation number?

A 3d¹4s²

B 3d² 4s²

C 3d⁵4s¹

D 3d⁵4s²

View Answer

Answer:3d⁵4s²

14 Identify disproportionation reaction

A CH4 + 202 → C02 + 2H20

B CH4 + 4C12 → CC14 + 4HCl

C 2F2 + 20H–→2F– + OF2 + H20

D 2N02 + 20H– → N02 + NO–3 + H20

View Answer

Answer:2N02 + 20H– → N02 + NO–3 + H20

15 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?

A The oxidation number of hydrogen is always +1.

B The algebraic sum of all the oxidation numbers in a compound is zero.

C An element in the free or the uncombined state bears oxidation number zero.

D In all its compounds, the oxidation number of fluorine is – 1.

View Answer

Answer:The oxidation number of hydrogen is always +1.

16 In which of the following compounds, an element exhibits two different oxidation states.

A NH₂OH

B NH₄NO₃

C N₂H₄

D N₃H

View Answer

Answer:N₂H₄

17 The more positive the value of E⊖ , the greater is the tendency of the species to get reduced. Using the standard electrode potential of redox couples given below find out which of the following is the strongest oxidising agent.

Redox Reactions