Quiz  /  Redox Reactions Class 12 MCQ Questions With Answers

  • 1. 
    _____________ synthesis and decomposition reactions involve the transfer of electrons.

  • All
  • Most
  • No
  • Some

  • 2. 
    What is the reducing agent here: N2 + 3H2 --> 2NH3

  • N2
  • H2
  • NH3
  • 2NH3

  • 3. 
    An element in a compound turns into an element in a chemical reaction. The element ...

  • is definitely oxidised
  • is definitely reduced
  • may have been oxidisied or reduced
  • is neither oxidised nor reduced

  • 4. 
    Bordo mix that is used in agriculture cannot be held in an iron container because iron reacts with the copper (II) sulphate. In the reaction, iron

  • is an oxidising agent
  • is a reducing agent
  • has a decrease in oxidation number
  • is reduced

  • 5. 
    What is the oxidation number of C in SrCO3?

  • -4
  • +2
  • -6
  • +4

  • 6. 
    Which particles DOES NOT have reducing power?

  • chloride ion
  • hydrogen ion
  • chlorine water
  • hydrogen gas

  • 7. 
    What element is being Reduced?

  • N
  • H
  • O
  • S

  • 8. 
    What element is being Oxidized?

  • N
  • H
  • O
  • S

  • 9. 
    What is oxidation number of H in H2O?

  • 0
  • -2
  • -1
  • +1

  • 10. 
    Combustion and single-replacement reactions are __________ redox reactions.

  • always
  • never
  • sometimes
  • mostly

  • 11. 
    What is the oxidizing agent of this reaction?3Mg + N2−−−−> Mg3N2

  • Mg
  • N2
  • Mg3N2
  • MgN

  • 12. 
    What is the species that gain electrons in a redox reaction?

  • oxidizing agent
  • reducing agent
  • is oxidized
  • increases in oxidation number

  • 13. 
    In the reaction Zn + 2HCl --> ZnCl2 + H2which element, if any, is oxidized?

  • Zinc
  • Hydrogen
  • Chlorine
  • None

  • 14. 
    Which of the following represents oxidation?

  • C → CH4
  • Fe3+ → Fe2+
  • Cl2 → 2Cl-
  • Zn → ZnO

  • 15. 
    What is the reducing agent of this reaction?3Mg + N2−−−−> Mg3N2

  • Mg
  • N2
  • Mg3N2
  • MgN

  • 16. 
    Which of the following represents reduction?

  • C →  CO
  • N2 →  NH3
  • Zn  →   Zn2+
  • H2 →  H2O

  • 17. 
    The sum of the oxidation numbers in Na2CO3 is equivalent to

  • 0
  • -2
  • +1
  • -1

  • 18. 
    What is the reducing agent of this reaction?2Al(s) + 6H+(aq) −−−> 2Al3+ (aq) + 3H2(g)

  • H+
  • Al3+
  • Al
  • H2

  • 19. 
    A redox reaction is NOT:

  • all reactions
  • a combustion reaction
  • a reduction-oxidation reaction
  • a reaction in which electrons are transferred from one atom to another

  • 20. 
    What is the species that lose electrons in a redox reaction?

  • oxidizing agent
  • reducing agent
  • is reduced
  • decreases in oxidation number

  • 21. 
    What is oxidation number of O in O2 ?

  • 0
  • -2
  • +1
  • +2

  • 22. 
    Which one below is redox reaction?

  • CaCO3+2HCl⟶CaCl2+CO2+H2OCaCO_3+2HCl\longrightarrow CaCl_2+CO_2+H_2OCaCO3​+2HCl⟶CaCl2​+CO2​+H2​O
  • CaO+H2O⟶Ca(OH)2CaO+H_2O\longrightarrow Ca\left(OH\right)_2CaO+H2​O⟶Ca(OH)2​
  • SO2+2H2S⟶3S+2H2OSO_2+2H_2S\longrightarrow3S+2H_2OSO2​+2H2​S⟶3S+2H2​O
  • NaCl+AgNO3⟶AgCl+NaNO3NaCl+AgNO_3\longrightarrow AgCl+NaNO_3NaCl+AgNO3​⟶AgCl+NaNO3​

  • 23. 
    The sum of the oxidation numbers in SCN- is equivalent to

  • 0
  • -1
  • +1
  • +3

  • 24. 
    What is the oxidation number of chlorine in HClO?

  • 0
  • -1
  • +1
  • +5

  • 25. 
    What is oxidation number of Fe in FeO ?

  • +2
  • -2
  • 0
  • +1

  • 26. 
    Oxygen always has an oxidation number of...

  • -1
  • 1
  • 2
  • -2
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