Class 11 Chemistry

1. Oxidation is defined as a process involving:

• A. Loss of electrons
• B. Gain of electrons
• C. Gain of hydrogen
• D. Decrease in oxidation number

2. What is the oxidation number of Manganese (Mn) in KMnO₄?

• A. +7
• B. +6
• C. +4
• D. +2

3. What is the oxidation number of Chromium (Cr) in K₂Cr₂O₇?

• A. +6
• B. +3
• C. +7
• D. +12

4. Reduction involves which of the following changes?

• A. Gain of electrons
• B. Loss of electrons
• C. Increase in oxidation number
• D. Loss of hydrogen

5. An oxidizing agent is a substance that:

• A. Accepts electrons and gets reduced
• B. Loses electrons and gets oxidized
• C. Increases its own oxidation number
• D. Donates protons

6. What is the oxidation number of Sulfur (S) in H₂SO₄?

• A. +6
• B. +4
• C. -2
• D. +2

7. Oxidation state of Oxygen in Hydrogen Peroxide (H₂O₂) is:

• A. -1
• B. -2
• C. 0
• D. +2

8. A reaction in which the same species undergoes oxidation as well as reduction is called:

• A. Disproportionation reaction
• B. Displacement reaction
• C. Combination reaction
• D. Decomposition reaction

9. What is the oxidation number of Phosphorus (P) in H₃PO₄?

• A. +5
• B. +3
• C. +1
• D. -3

10. What is the oxidation state of Oxygen in OF₂ (Oxygen Difluoride)?

• A. +2
• B. -2
• C. -1
• D. +1

11. In the reaction CuO + H₂ → Cu + H₂O, the reducing agent is:

• A. H₂
• B. CuO
• C. Cu
• D. H₂O

12. What is the oxidation number of Iron (Fe) in Fe₃O₄?

• A. +8/3
• B. +2
• C. +3
• D. +6

13. In a Galvanic cell, oxidation takes place at the:

• A. Anode
• B. Cathode
• C. Salt bridge
• D. Electrolyte solution

14. What is the main function of a salt bridge in an electrochemical cell?

• A. Maintains electrical neutrality of both half-cells
• B. Allows movement of electrons
• C. Increases voltage output
• D. Prevents mixing of gases

15. What is the oxidation state of Carbon in C₆H₁₂O₆ (Glucose)?

• A. 0
• B. +2
• C. +4
• D. -2

16. Standard Hydrogen Electrode (SHE) is assigned a standard electrode potential of:

• A. 0.00 V
• B. 1.00 V
• C. -1.00 V
• D. 0.059 V

17. Which of the following elements exhibits only a single negative oxidation state in its compounds?

• A. Fluorine
• B. Oxygen
• C. Chlorine
• D. Nitrogen

18. What is the oxidation number of Chlorine (Cl) in CaOCl₂ (Bleaching powder)?

• A. -1 and +1
• B. +2 and -2
• C. 0
• D. +1 only

19. In acidic medium, KMnO₄ acts as a strong oxidizing agent and reduces to:

• A. Mn²⁺
• B. MnO₂
• C. MnO₄²⁻
• D. Mn³⁺

20. Which of the following is NOT a redox reaction?

• A. AgNO₃ + NaCl → AgCl + NaNO₃
• B. 2H₂ + O₂ → 2H₂O
• C. Zn + 2HCl → ZnCl₂ + H₂
• D. CH₄ + 2O₂ → CO₂ + 2H₂O

21. What is the oxidation state of Nitrogen in NH₄NO₃ (Ammonium Nitrate)?

• A. -3 and +5
• B. -3 only
• C. +5 only
• D. +1 and +3

22. The species having the highest reducing power has the:

• A. Most negative reduction potential
• B. Most positive reduction potential
• C. Zero reduction potential
• D. Highest oxidation state

23. What is the oxidation state of Chlorine in HClO₄ (Perchloric acid)?

• A. +7
• B. +5
• C. +1
• D. -1

24. What is the oxidation state of Hydrogen in Metal Hydrides like NaH?

• A. -1
• B. +1
• C. 0
• D. +2

25. In neutral or weakly alkaline medium, KMnO₄ reduces to:

• A. MnO₂
• B. Mn²⁺
• C. MnO₄²⁻
• D. Mn₂O₃

26. Oxidation number of Sulfur in Sodium Thiosulfate (Na₂S₂O₃) is:

• A. +2
• B. +2.5
• C. +6
• D. +4

27. Which method is commonly used to balance complex redox equations?

• A. Ion-electron (Half-reaction) method
• B. Trial and error method
• C. Gravimetric method
• D. Volumetric method

28. What is the oxidation state of Xe in XeF₄?

• A. +4
• B. +2
• C. +6
• D. 0

29. When H₂S gas is passed through acidic K₂Cr₂O₇ solution, color changes from orange to green due to formation of:

• A. Cr³⁺ ions
• B. Cr⁶⁺ ions
• C. SO₂ gas
• D. S²⁻ ions

30. What is the oxidation state of Nickel in Ni(CO)₄?

• A. 0
• B. +2
• C. +4
• D. -2