Redox Reactions

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1. What happens in an Oxidation reaction?
(A) Protons are lost
(B) Electrons are lost
(C) Neutrons are lost
(D) Electrons are gained
Ans. (B)

2. Wh ich among the fo llowing is not a characteristic of Oxidation reaction ?
(A) It involves addition of hydrogen
(B) It involves addition of oxygen
(C) It involves loss of electrons
(D) It involves addition of electronegative element
Ans. (A)

3. The liberation of oxygen during photosynthesis is due to__________.
(A) Hydrolysis of carbohydrates
(B) Photolysis of water
(C) Reduction of CO2
(D) Breakdown of chlorophyll
Ans. (B)

4. When Hydrogen combusts in air, then formed–
(A) Ammonia (B) Water
(C) Methane (D) Carbonic acid.
Ans. (B)

5. Browning of paper in old books is caused by
(A) Frequent use
(B) Lack of aeration
(C) Collection of dust
(D) Oxidation of cellulose
Ans. (D)

6. Oxygen has (+) oxidation number only in
(A) OF2
(B) Cl2O
(C) H2 O
(D) N2O
Ans. (A)

7. The oxidation number of nickel in K4[Ni(CN)4] is
(A) 0
(B) +4
(C) –4
(D) +8
Ans. (A)

8. The oxidation number of sulphur in S8, S2F2 and H2S respectively are
(A) 0, +1 and –2
(B) + 2, +1 and –2
(C) 0, +1 and +2
(D) –2 , +1 and –2
Ans. (A)

9. Nitrogen forms a variety of compounds in all oxidation states ranging from–
(A) – 3 to +5
(B) –3 to +3
(C) –3 to +4
(D) –3 to +6
Ans. (A)

10. Oxidation state of Fe in Fe3O4 is –
(A) 32 (B)45
(C) 54 (D)83
Ans. (D)

11. The oxidation state of Cr in K2Cr2O7 is –
(A) +7 (B) +6
(C) +3 (D) +2
Ans. (B)

12. In H2O2, oxidation state of oxygen is
(A) –2 (B) –1
(C) .0 (D) –4
Ans. (B)

13. In which of the following compounds transition metal has zero oxidation state?
(A) CrO5
(B) Fe3O4
(C) FeSO4
(D) Fe(CO)5
Ans. (D)

14. Cooking oil is converted into vegetable ghee by the process of–
(A) Hydrogenation
(B) Oxidation
(C) Condensation
(D) Crystallization
Ans. (A)

16. Rusting of Iron is –
(A) Due to oxidation
(B) Due to carbonation
(C) Due to epoxidation
(D) Due to corrosion
Ans. (A)

17. The rusting of iron metal in air needs both–
(A) Carbon dioxide and Moisture
(B) Water and Paint
(C) Oxygen and grease
(D) Oxygen and Moisture
Ans. (D)

18. What is Rusting of Iron?
(A) Physical change
(B) Electric change
(C) Photo Chemical change
(D) None of the above
Ans. (D)

19. Iron rusts quickly in –
(A) Rain water
(B) Distilled water
(C) Sea water
(D) River water
Ans. (C)

20. The rusting of iron–
(A) Decreases its weight
(B) Increases its weight
(C) Remains same
(D) Can’t say (unpredictable)
Ans. (B)

21. The coating of thin layer of zinc on steel or iron object is known as
(A) Hot dipping
(B) Tinning
(C) Galvanising
(D) Electroplating
Ans. (C)

22. The metal, used to galvanise iron to protect it from rusting is
(A) Zinc
(B) Chromium
(C) Lead
(D) Antimony
Ans. (A)

23. Which metal does not undergo corrosion due to the formation of Oxide layer?
(A) Copper
(B) Iron
(C) Aluminium
(D) Zinc
Ans. (C)
24. The metal chiefly used for galvanising iron is:
(A) Zinc
(B) Mercury
(C) Cadmium
(D) Tin
Ans. (A)

25. The process of deposition of a layer of Zinc over water pipes for being protected from rusting is known as–
(A) Depositing a Layer of Zinc
(B) Formation of alloy
(C) Vulcanization
(D) Galvanization
Ans. (D)

26. Which metal is used to Galvanize iron?
(A) Copper
(B) Zinc
(C) Tin
(D) Nickel
Ans. (B)

27. To protect the iron from getting rusted, the coat of zinc is applied on it. This process is known as–
(A) Galvanization
(B) Reduction
(C) Corrosion
(D) Calcination
Ans. (A)

28. Which of the following is not favourable to prevent iron from rusting?
(A) Annealing
(B) Applying grease
(C) Galvanization
(D) Painting
Ans. (A)

29. Potassium Permanganate is used for purifying drinking water, because_________
(A) It is a reducing agent
(B) It is an oxidising agent
(C) It is a sterilising agent
(D) It dissolves the impurities of water
Ans. (B)

30. Carbon dioxide is
(A) A Reducing agent
(B) An Oxidising agent
(C) A Dehydrating agent
(D) A Bleaching agent
Ans. (B)

31. The reactions in which oxidation and reduction occur simultaneously are called___.
(A) Feral reactions
(B) Redox reactions
(C) Demug reactions
(D) Kerol reactions
Ans. (B)

32. Rusting is _____.
(A) Electrolysis
(B) Oxidation
(C) Redox reaction (Oxidation and Reduction)
(D) Reduction
Ans. (B)

33. Which among the following metal is used for galvanization?
(A) Zinc (B) Copper
(C) Iron (D) Silver
Ans. (A)

34. Process of gaining electrons is known as _____.
(A) Oxidation
(B) Reduction
(C) Radiation
(D) Both oxidation and reduction
Ans. (B)

35. Process of loosing electrons is known as _____.
(A) Oxidation
(B) Reduction
(C) Radiation
(D) Both oxidation and reduction
Ans. (A)

36. What is the process of rust forming on iron called?
(A) Rusting
(B) Crystallisation
(C) Shovel
(D) Spade
Ans. (A)

37. The process of deposition of a layer of zinc on iron is called ___________ .
(A) Galvanisation
(B) Crystallisation
(C) Rusting
(D) Baking
Ans. (A)

38. The process of deposition of a layer of any desired metal on another material by means of
electricity is called ___________.
(A) Electroplating
(B) Galvanisation
(C) Rusting
(D) Crystallisation
Ans. (A)

39. Brownish film formed on iron when left in open is called?
(A) Dust
(B) Shovel
(C) Spade
(D) Rust
Ans. (D)

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