{"id":12815,"date":"2025-09-23T12:44:55","date_gmt":"2025-09-23T11:44:55","guid":{"rendered":"https:\/\/mcqsadda.com\/?p=12815"},"modified":"2025-10-22T10:35:28","modified_gmt":"2025-10-22T09:35:28","slug":"catalyst-top-100-mcqs-with-answer-and-explanation","status":"publish","type":"post","link":"https:\/\/mcqsadda.com\/index.php\/2025\/09\/23\/catalyst-top-100-mcqs-with-answer-and-explanation\/","title":{"rendered":"Catalyst Top 100 MCQs With Answer and Explanation"},"content":{"rendered":"\n

1. A catalyst is a substance that:<\/strong><\/mark>
A) Increases activation energy
B) Increases equilibrium constant
C) Speeds up the reaction without being consumed
D) Gets permanently consumed in the reaction
Answer:<\/strong> C
Explanation:<\/strong> A catalyst lowers activation energy and accelerates the reaction without itself being consumed.<\/p>\n\n\n\n

2. Which of the following is not<\/em> a characteristic of a catalyst?
<\/mark><\/strong>A) It remains unchanged at the end
B) It alters equilibrium constant
C) It alters rate of reaction
D) It functions even in small amounts
Answer:<\/strong> B
Explanation:<\/strong> Catalysts do not change the equilibrium constant; they only help reach equilibrium faster.<\/p>\n\n\n\n

3. The branch of chemistry that deals with catalysts is called:
<\/mark><\/strong>A) Thermodynamics
B) Catalysis
C) Photochemistry
D) Electrochemistry
Answer:<\/strong> B
Explanation:<\/strong> Catalysis is the study of catalysts and catalytic processes.<\/p>\n\n\n\n

4. Which of the following is a homogeneous catalyst?
<\/strong><\/mark>A) V\u2082O\u2085 in Contact process
B) Fe in Haber\u2019s process
C) H\u207a ions in ester hydrolysis
D) Ni in hydrogenation
Answer:<\/strong> C
Explanation:<\/strong> Homogeneous catalysts exist in the same phase as reactants, e.g., H\u207a ions in ester hydrolysis.<\/p>\n\n\n\n

5. Which of the following is a heterogeneous catalyst?
<\/mark><\/strong>A) HCl in hydrolysis
B) NO in oxidation of SO\u2082
C) Pt in hydrogenation
D) H\u2082SO\u2084 in esterification
Answer:<\/strong> C
Explanation:<\/strong> In hydrogenation, solid Pt acts as a catalyst for gaseous reactants \u2192 heterogeneous catalysis.<\/p>\n\n\n\n

6. Which catalyst is used in the Haber\u2019s process for ammonia synthesis?
<\/strong><\/mark>A) V\u2082O\u2085
B) Fe
C) Pt
D) MnO\u2082
Answer:<\/strong> B
Explanation:<\/strong> Iron catalyst is used in the Haber process (with promoters like K\u2082O, Al\u2082O\u2083).<\/p>\n\n\n\n

7. In the Contact process (manufacture of H\u2082SO\u2084), the catalyst used is:
<\/mark><\/strong>A) Fe\u2082O\u2083
B) V\u2082O\u2085
C) Ni
D) Pt
Answer:<\/strong> B
Explanation:<\/strong> Vanadium pentoxide (V\u2082O\u2085) catalyzes oxidation of SO\u2082 to SO\u2083.<\/p>\n\n\n\n

8. Which type of catalysis does hydrogenation of vegetable oils using Ni belong to?
<\/mark><\/strong>A) Homogeneous
B) Heterogeneous
C) Autocatalysis
D) Negative catalysis
Answer:<\/strong> B
Explanation:<\/strong> Solid Ni catalyst with liquid oil and gaseous H\u2082 \u2192 heterogeneous catalysis.<\/p>\n\n\n\n

9. Enzymes act as:
<\/mark><\/strong>A) Negative catalysts
B) Homogeneous catalysts
C) Heterogeneous catalysts
D) Inhibitors
Answer:<\/strong> B
Explanation:<\/strong> Enzymes act in the same aqueous phase as the substrate \u2192 homogeneous catalysis.<\/p>\n\n\n\n

10. The \u201clock and key\u201d model is associated with:
<\/mark><\/strong>A) Autocatalysis
B) Enzyme catalysis
C) Inhibition
D) Surface catalysis
Answer:<\/strong> B
Explanation:<\/strong> The model explains how enzymes specifically bind substrates.<\/p>\n\n\n\n

11. The catalyst in the Ostwald process (manufacture of nitric acid) is:
<\/mark><\/strong>A) V\u2082O\u2085
B) Pt-Rh gauze
C) Fe
D) Ni
Answer:<\/strong> B
Explanation:<\/strong> Pt-Rh gauze catalyzes oxidation of NH\u2083 to NO.<\/p>\n\n\n\n

12. Catalytic converters in automobiles typically use:
<\/mark><\/strong>A) Fe and Cu
B) Pt, Pd, and Rh
C) Ni and Zn
D) Mn and Cr
Answer:<\/strong> B
Explanation:<\/strong> Platinum, Palladium, and Rhodium catalyze oxidation of CO and hydrocarbons, and reduction of NOx.<\/p>\n\n\n\n

13. The process where product itself acts as a catalyst is called:
<\/mark><\/strong>A) Homogeneous catalysis
B) Autocatalysis
C) Heterogeneous catalysis
D) Inhibition
Answer:<\/strong> B
Explanation:<\/strong> In autocatalysis, the reaction product accelerates the reaction.<\/p>\n\n\n\n

14. Which is an example of autocatalysis?
<\/mark><\/strong>A) Ester hydrolysis
B) Oxidation of SO\u2082
C) Decomposition of oxalic acid by KMnO\u2084
D) Haber\u2019s process
Answer:<\/strong> C
Explanation:<\/strong> Mn\u00b2\u207a formed in the reaction catalyzes further decomposition \u2192 autocatalysis.<\/p>\n\n\n\n

15. Negative catalysts are also called:
<\/mark><\/strong>A) Promoters
B) Poisons
C) Enzymes
D) Substrates
Answer:<\/strong> B
Explanation:<\/strong> Poisons slow down reactions by destroying catalyst activity.<\/p>\n\n\n\n

16. A promoter in catalysis is:
<\/mark><\/strong>A) A substance that increases efficiency of a catalyst
B) A catalyst inhibitor
C) An alternative reactant
D) A solvent
Answer:<\/strong> A
Explanation:<\/strong> Promoters enhance activity of catalysts (e.g., K\u2082O in Haber\u2019s process).<\/p>\n\n\n\n

17. Example of promoter in Haber\u2019s process is:
<\/mark><\/strong>A) Al\u2082O\u2083
B) K\u2082O
C) Both A and B
D) NaCl
Answer:<\/strong> C
Explanation:<\/strong> Al\u2082O\u2083 and K\u2082O increase efficiency of Fe catalyst.<\/p>\n\n\n\n

18. Which reaction uses MnO\u2082 as a catalyst?
<\/mark><\/strong>A) Decomposition of H\u2082O\u2082
B) Oxidation of SO\u2082
C) Haber\u2019s process
D) Esterification
Answer:<\/strong> A
Explanation:<\/strong> MnO\u2082 catalyzes decomposition of hydrogen peroxide into water and oxygen.<\/p>\n\n\n\n

19. Which catalyst is used in hydrogenation of oils?
<\/mark><\/strong>A) V\u2082O\u2085
B) Fe
C) Ni
D) Pt
Answer:<\/strong> C
Explanation:<\/strong> Finely divided Nickel is most common hydrogenation catalyst.<\/p>\n\n\n\n

20. Which catalyst is used in Deacon\u2019s process (manufacture of Cl\u2082)?
<\/mark><\/strong>A) V\u2082O\u2085
B) CuCl\u2082
C) Fe\u2082O\u2083
D) Ni
Answer:<\/strong> B
Explanation:<\/strong> CuCl\u2082 catalyzes oxidation of HCl to Cl\u2082.<\/p>\n\n\n\n

21. Which is an example of heterogeneous catalysis?
<\/mark><\/strong>A) Hydrolysis of esters
B) Oxidation of SO\u2082 by NO
C) Haber\u2019s process (Fe catalyst)
D) Enzyme action
Answer:<\/strong> C
Explanation:<\/strong> Fe solid catalyst with gaseous reactants is heterogeneous.<\/p>\n\n\n\n

22. Catalysis in which reactants and catalyst are in same phase is called:
<\/mark><\/strong>A) Homogeneous catalysis
B) Heterogeneous catalysis
C) Autocatalysis
D) Enzyme catalysis
Answer:<\/strong> A
Explanation:<\/strong> Same phase \u2192 homogeneous catalysis.<\/p>\n\n\n\n

23. Catalysis in which reactants and catalyst are in different phases is called:
<\/mark><\/strong>A) Homogeneous
B) Heterogeneous
C) Enzyme
D) Inhibition
Answer:<\/strong> B
Explanation:<\/strong> Different phases \u2192 heterogeneous catalysis.<\/p>\n\n\n\n

24. The most efficient catalysts are:
<\/strong><\/mark>A) Metals
B) Acids
C) Enzymes
D) Alkalis
Answer:<\/strong> C
Explanation:<\/strong> Enzymes (biocatalysts) are highly efficient and specific.<\/p>\n\n\n\n

25. The theory explaining heterogeneous catalysis is:
<\/mark><\/strong>A) Collision theory
B) Intermediate compound theory
C) Adsorption theory
D) Quantum theory
Answer:<\/strong> C
Explanation:<\/strong> Adsorption theory explains catalytic action on solid surfaces.<\/p>\n\n\n\n

26. The adsorption theory of catalysis is mainly applicable to:
<\/mark><\/strong>A) Homogeneous catalysis
B) Heterogeneous catalysis
C) Autocatalysis
D) Enzyme catalysis
Answer:<\/strong> B
Explanation:<\/strong> Adsorption theory explains surface catalysis in heterogeneous reactions.<\/p>\n\n\n\n

27. According to adsorption theory, the role of catalyst is to:
<\/mark><\/strong>A) Increase temperature of reactants
B) Increase concentration of products
C) Provide a surface for adsorption of reactants
D) Change equilibrium constant
Answer:<\/strong> C
Explanation:<\/strong> Catalyst surface adsorbs reactants, weakens bonds, and facilitates reaction.<\/p>\n\n\n\n

28. In heterogeneous catalysis, reactants are adsorbed on the surface by:
<\/strong><\/mark>A) Diffusion
B) Condensation
C) Adsorption forces
D) Hydrogen bonding
Answer:<\/strong> C
Explanation:<\/strong> Adsorption forces (physisorption or chemisorption) hold molecules on catalyst surface.<\/p>\n\n\n\n

29. Which type of adsorption is more important in catalysis?
<\/mark><\/strong>A) Physical adsorption
B) Chemical adsorption
C) Capillary adsorption
D) Molecular adsorption
Answer:<\/strong> B
Explanation:<\/strong> Chemisorption forms strong bonds, activating molecules for reaction.<\/p>\n\n\n\n

30. Which of the following is an example of adsorption catalysis?
<\/mark><\/strong>A) Hydrolysis of ester by acid
B) Hydrogenation of ethene on Ni
C) Decomposition of ozone by Cl atoms
D) Decomposition of H\u2082O\u2082 by I\u207b
Answer:<\/strong> B
Explanation:<\/strong> Hydrogenation occurs via chemisorption of H\u2082 and alkene on Ni surface.<\/p>\n\n\n\n

31. Which factor does not affect adsorption catalysis?
<\/mark><\/strong>A) Surface area of catalyst
B) Temperature
C) Presence of promoter or poison
D) Avogadro number
Answer:<\/strong> D
Explanation:<\/strong> Adsorption depends on surface, temp, and promoters\/poisons, not on Avogadro constant.<\/p>\n\n\n\n

32. A catalyst increases the rate of reaction because:
<\/mark><\/strong>A) It increases collision frequency
B) It decreases activation energy
C) It increases heat of reaction
D) It alters equilibrium
Answer:<\/strong> B
Explanation:<\/strong> Catalyst provides an alternative pathway with lower activation energy.<\/p>\n\n\n\n

33. Which is correct regarding catalyst action?
<\/strong><\/mark>A) Catalyst changes \u0394G of reaction
B) Catalyst changes enthalpy of reaction
C) Catalyst changes activation energy
D) Catalyst shifts equilibrium
Answer:<\/strong> C
Explanation:<\/strong> Only activation energy is altered; \u0394G, \u0394H, equilibrium remain unchanged.<\/p>\n\n\n\n

34. Which catalyst is used in hydrogenation of benzene to cyclohexane?
<\/mark><\/strong>A) Ni
B) Fe
C) V\u2082O\u2085
D) Pt
Answer:<\/strong> A
Explanation:<\/strong> Finely divided Ni catalyzes hydrogenation of benzene.<\/p>\n\n\n\n

35. Which process uses Fe as a catalyst?
<\/mark><\/strong>A) Ostwald process
B) Haber process
C) Contact process
D) Deacon\u2019s process
Answer:<\/strong> B
Explanation:<\/strong> Haber process (NH\u2083 manufacture) uses Fe catalyst with promoters.<\/p>\n\n\n\n

36. Which process uses V\u2082O\u2085 as a catalyst?
<\/mark><\/strong>A) Ostwald process
B) Contact process
C) Haber process
D) Deacon\u2019s process
Answer:<\/strong> B
Explanation:<\/strong> Contact process for SO\u2082 \u2192 SO\u2083 uses V\u2082O\u2085.<\/p>\n\n\n\n

37. Which catalyst is used in Ostwald process?
<\/strong><\/mark>A) Pt-Rh gauze
B) V\u2082O\u2085
C) Ni
D) Fe
Answer:<\/strong> A
Explanation:<\/strong> Ammonia oxidation uses Pt-Rh catalyst.<\/p>\n\n\n\n

38. Which catalyst is used in the synthesis of methanol from CO and H\u2082?
<\/mark><\/strong>A) Fe
B) Cu-ZnO-Al\u2082O\u2083
C) Pt
D) Ni
Answer:<\/strong> B
Explanation:<\/strong> Methanol synthesis uses Cu-ZnO-Al\u2082O\u2083 catalyst.<\/p>\n\n\n\n

39. Which process uses Ziegler\u2013Natta catalyst?
<\/mark><\/strong>A) Production of NH\u2083
B) Hydrogenation of oils
C) Polymerization of alkenes
D) Manufacture of H\u2082SO\u2084
Answer:<\/strong> C
Explanation:<\/strong> Ziegler\u2013Natta catalysts (TiCl\u2084 + AlEt\u2083) are used for alkene polymerization.<\/p>\n\n\n\n

40. What is the function of promoters in catalysis?
<\/mark><\/strong>A) To increase activity of catalyst
B) To decrease catalyst efficiency
C) To stop catalyst poisoning
D) To act as secondary reactant
Answer:<\/strong> A
Explanation:<\/strong> Promoters enhance activity of catalysts without themselves being catalysts.<\/p>\n\n\n\n

41. Example of a promoter in Haber\u2019s process is:
<\/mark><\/strong>A) Cu
B) K\u2082O
C) ZnO
D) MnO\u2082
Answer:<\/strong> B
Explanation:<\/strong> K\u2082O and Al\u2082O\u2083 promote Fe catalyst in ammonia synthesis.<\/p>\n\n\n\n

42. Catalyst poison in Haber\u2019s process is:
<\/mark><\/strong>A) H\u2082S
B) O\u2082
C) H\u2082O
D) N\u2082
Answer:<\/strong> A
Explanation:<\/strong> H\u2082S deactivates Fe catalyst by poisoning.<\/p>\n\n\n\n

43. Which industrial process uses Ni as catalyst?
<\/mark><\/strong>A) Haber process
B) Contact process
C) Hydrogenation of oils
D) Ostwald process
Answer:<\/strong> C
Explanation:<\/strong> Nickel catalyzes hydrogenation of vegetable oils.<\/p>\n\n\n\n

44. Which industrial process uses CuCl\u2082 as a catalyst?
<\/mark><\/strong>A) Deacon\u2019s process
B) Contact process
C) Ostwald process
D) Haber process
Answer:<\/strong> A
Explanation:<\/strong> CuCl\u2082 catalyzes HCl oxidation in Deacon\u2019s process.<\/p>\n\n\n\n

45. Which process uses TiCl\u2084 and Al(C\u2082H\u2085)\u2083 as catalysts?
<\/mark><\/strong>A) Haber process
B) Ziegler\u2013Natta polymerization
C) Ostwald process
D) Contact process
Answer:<\/strong> B
Explanation:<\/strong> Ziegler\u2013Natta catalysts for polyethylene\/polypropylene manufacture.<\/p>\n\n\n\n

46. The role of catalyst in chemical reaction is to:
<\/strong><\/mark>A) Change heat of reaction
B) Increase \u0394H of system
C) Provide alternate pathway with lower activation energy
D) Increase product concentration
Answer:<\/strong> C
Explanation:<\/strong> Catalyst lowers activation energy by offering alternate mechanism.<\/p>\n\n\n\n

47. Which is an example of catalytic converter in cars?
<\/mark><\/strong>A) Ni
B) Pt-Pd-Rh
C) Fe
D) V\u2082O\u2085
Answer:<\/strong> B
Explanation:<\/strong> Pt, Pd, and Rh catalysts are used in vehicle catalytic converters.<\/p>\n\n\n\n

48. Which type of catalyst is Ziegler\u2013Natta catalyst?
<\/mark><\/strong>A) Homogeneous
B) Heterogeneous
C) Enzyme
D) Negative
Answer:<\/strong> B
Explanation:<\/strong> Solid TiCl\u2084 and AlEt\u2083 catalysts are heterogeneous.<\/p>\n\n\n\n

49. Which of the following is an example of a negative catalyst?
<\/mark><\/strong>A) Glycerol in decomposition of H\u2082O\u2082
B) MnO\u2082 in decomposition of H\u2082O\u2082
C) V\u2082O\u2085 in Contact process
D) Ni in hydrogenation
Answer:<\/strong> A
Explanation:<\/strong> Glycerol slows decomposition of H\u2082O\u2082 \u2192 negative catalyst.<\/p>\n\n\n\n

50. Which is an example of catalytic hydrogenation?
<\/mark><\/strong>A) C\u2082H\u2084 \u2192 C\u2082H\u2086 using Ni
B) H\u2082O\u2082 \u2192 H\u2082O + O\u2082 using MnO\u2082
C) NH\u2083 \u2192 NO using Pt
D) SO\u2082 \u2192 SO\u2083 using V\u2082O\u2085
Answer:<\/strong> A
Explanation:<\/strong> Nickel catalyzes hydrogenation of ethene to ethane.<\/p>\n\n\n\n

51. Enzymes are chemically:
<\/mark><\/strong>A) Carbohydrates
B) Proteins
C) Lipids
D) Nucleic acids
Answer:<\/strong> B
Explanation:<\/strong> Enzymes are biological catalysts made of proteins (sometimes conjugated with cofactors).<\/p>\n\n\n\n

52. Which of the following is not<\/em> an enzyme?
<\/strong><\/mark>A) Urease
B) Amylase
C) Catalase
D) Insulin
Answer:<\/strong> D
Explanation:<\/strong> Insulin is a hormone, not an enzyme.<\/p>\n\n\n\n

53. The enzyme that catalyzes decomposition of H\u2082O\u2082 into water and oxygen is:
<\/mark><\/strong>A) Amylase
B) Catalase
C) Urease
D) Lipase
Answer:<\/strong> B
Explanation:<\/strong> Catalase rapidly decomposes hydrogen peroxide.<\/p>\n\n\n\n

54. Enzyme catalysis is an example of:
<\/mark><\/strong>A) Homogeneous catalysis
B) Heterogeneous catalysis
C) Autocatalysis
D) Negative catalysis
Answer:<\/strong> A
Explanation:<\/strong> Enzyme and substrate are usually in same aqueous phase \u2192 homogeneous catalysis.<\/p>\n\n\n\n

55. The \u201clock and key\u201d hypothesis was proposed by:
<\/strong><\/mark>A) Arrhenius
B) Berzelius
C) Fischer
D) Ostwald
Answer:<\/strong> C
Explanation:<\/strong> Emil Fischer (1894) proposed \u201clock and key\u201d model of enzyme action.<\/p>\n\n\n\n

56. The enzyme that converts glucose into ethanol and CO\u2082 is:
<\/strong><\/mark>A) Zymase
B) Invertase
C) Maltase
D) Amylase
Answer:<\/strong> A
Explanation:<\/strong> Zymase in yeast catalyzes alcoholic fermentation of glucose.<\/p>\n\n\n\n

57. The enzyme used in hydrolysis of urea is:
<\/mark><\/strong>A) Zymase
B) Urease
C) Catalase
D) Amylase
Answer:<\/strong> B
Explanation:<\/strong> Urease catalyzes conversion of urea into NH\u2083 and CO\u2082.<\/p>\n\n\n\n

58. Which of the following is an example of enzyme catalysis in the human body?
<\/mark><\/strong>A) Hydrolysis of starch by amylase
B) SO\u2082 oxidation by V\u2082O\u2085
C) Hydrogenation by Ni
D) NH\u2083 synthesis by Fe
Answer:<\/strong> A
Explanation:<\/strong> Amylase in saliva hydrolyzes starch to maltose.<\/p>\n\n\n\n

59. The efficiency of enzymes is highest at:
<\/mark><\/strong>A) Low temperature
B) Optimum temperature and pH
C) Very high temperature
D) Any condition
Answer:<\/strong> B
Explanation:<\/strong> Enzymes work best at an optimum temperature and pH (e.g., 37 \u00b0C for human enzymes).<\/p>\n\n\n\n

60. Which is an example of autocatalysis?
<\/mark><\/strong>A) Hydrolysis of esters
B) Oxidation of SO\u2082
C) Decomposition of oxalic acid by KMnO\u2084
D) Haber process
Answer:<\/strong> C
Explanation:<\/strong> Mn\u00b2\u207a formed in the reaction accelerates further decomposition.<\/p>\n\n\n\n

61. Autocatalysis is a process in which:
<\/mark><\/strong>A) Reactants act as catalyst
B) Products act as catalyst
C) Promoters act as catalyst
D) Solvent acts as catalyst
Answer:<\/strong> B
Explanation:<\/strong> In autocatalysis, the product of reaction accelerates the same reaction.<\/p>\n\n\n\n

62. Which is a classical example of autocatalysis?
<\/mark><\/strong>A) Esterification
B) Decomposition of oxalic acid by KMnO\u2084
C) Haber\u2019s process
D) Contact process
Answer:<\/strong> B
Explanation:<\/strong> Mn\u00b2\u207a ions formed act as catalyst in further decomposition.<\/p>\n\n\n\n

63. Negative catalysis is also known as:
<\/strong><\/mark>A) Catalysis
B) Inhibition
C) Promotion
D) Adsorption
Answer:<\/strong> B
Explanation:<\/strong> Negative catalysts (poisons) reduce rate of reaction by inhibiting catalyst action.<\/p>\n\n\n\n

64. An example of negative catalysis is:
<\/mark><\/strong>A) MnO\u2082 in H\u2082O\u2082 decomposition
B) Glycerol in decomposition of H\u2082O\u2082
C) Pt in H\u2082 + O\u2082 reaction
D) Ni in hydrogenation
Answer:<\/strong> B
Explanation:<\/strong> Glycerol retards decomposition of H\u2082O\u2082.<\/p>\n\n\n\n

65. Which of the following is a negative catalyst for oxidation of chloroform?
<\/mark><\/strong>A) Alcohol
B) Phenol
C) Oxygen
D) Acetic acid
Answer:<\/strong> A
Explanation:<\/strong> Ethyl alcohol prevents oxidation of chloroform to poisonous phosgene \u2192 negative catalyst.<\/p>\n\n\n\n

66. The theory of intermediate compound formation explains:
<\/mark><\/strong>A) Homogeneous catalysis
B) Heterogeneous catalysis
C) Negative catalysis
D) Autocatalysis
Answer:<\/strong> A
Explanation:<\/strong> In homogeneous catalysis, catalyst reacts with reactant to form unstable intermediate \u2192 speeds up reaction.<\/p>\n\n\n\n

67. Which theory explains heterogeneous catalysis?
<\/mark><\/strong>A) Collision theory
B) Adsorption theory
C) Intermediate compound theory
D) Chain reaction theory
Answer:<\/strong> B
Explanation:<\/strong> Adsorption theory explains heterogeneous catalysis on solid surfaces.<\/p>\n\n\n\n

68. In intermediate compound theory, catalyst:
<\/mark><\/strong>A) Forms stable compounds with reactants
B) Forms unstable intermediates with reactants
C) Forms permanent compounds with products
D) Remains unreactive
Answer:<\/strong> B
Explanation:<\/strong> Catalyst forms unstable intermediates that decompose to products, regenerating catalyst.<\/p>\n\n\n\n

69. The main difference between positive and negative catalysis is:
<\/mark><\/strong>A) Positive catalyst increases rate, negative decreases it
B) Positive catalyst decreases rate, negative increases it
C) Both increase rate
D) Both decrease rate
Answer:<\/strong> A
Explanation:<\/strong> Positive \u2192 increases rate; Negative \u2192 retards reaction.<\/p>\n\n\n\n

70. Which of the following is a catalytic poison?<\/mark><\/strong>
A) H\u2082S for Fe in Haber process
B) Al\u2082O\u2083 for Fe in Haber process
C) K\u2082O for Fe in Haber process
D) Pt for NH\u2083 oxidation
Answer:<\/strong> A
Explanation:<\/strong> H\u2082S poisons Fe catalyst in Haber process.<\/p>\n\n\n\n

71. Which factor strongly influences enzyme catalysis?
<\/mark><\/strong>A) Temperature and pH
B) Only pressure
C) Only concentration of substrate
D) Only surface area
Answer:<\/strong> A
Explanation:<\/strong> Enzyme activity depends heavily on optimum temperature and pH.<\/p>\n\n\n\n

72. Enzyme catalysis is often described by:
<\/mark><\/strong>A) Adsorption theory
B) Intermediate compound theory
C) Lock and key hypothesis
D) Arrhenius equation
Answer:<\/strong> C
Explanation:<\/strong> Lock and key model best explains enzyme action.<\/p>\n\n\n\n

73. The efficiency of catalysis depends upon:
<\/mark><\/strong>A) Activation energy
B) Heat of reaction
C) Equilibrium constant
D) Specific heat
Answer:<\/strong> A
Explanation:<\/strong> Lower the activation energy by catalyst, higher the efficiency.<\/p>\n\n\n\n

74. Which theory can explain both homogeneous and enzyme catalysis?
<\/mark><\/strong>A) Adsorption theory
B) Intermediate compound theory
C) Collision theory
D) Lock and key model
Answer:<\/strong> B
Explanation:<\/strong> Intermediate compound theory applies well to homogeneous and enzyme catalysis.<\/p>\n\n\n\n

75. A catalyst that stops working due to poisoning can sometimes be restored by:
<\/mark><\/strong>A) Increasing reactant concentration
B) Removing the poison
C) Adding heat of reaction
D) Adding more products
Answer:<\/strong> B
Explanation:<\/strong> Removal of catalyst poison can restore catalytic activity.<\/p>\n\n\n\n

76. Which catalyst is used in the manufacture of nitric acid (Ostwald process)?
<\/mark><\/strong>A) Fe
B) Pt-Rh gauze
C) V\u2082O\u2085
D) Ni
Answer:<\/strong> B
Explanation:<\/strong> In Ostwald process, Pt-Rh gauze catalyzes oxidation of NH\u2083 to NO.<\/p>\n\n\n\n

77. Which process uses Fe catalyst with promoters K\u2082O and Al\u2082O\u2083?
<\/mark><\/strong>A) Contact process
B) Haber process
C) Ostwald process
D) Deacon\u2019s process
Answer:<\/strong> B
Explanation:<\/strong> Haber process (ammonia synthesis) uses Fe with promoters.<\/p>\n\n\n\n

78. Which catalyst is used in hydrogenation of oils?
<\/mark><\/strong>A) Ni
B) V\u2082O\u2085
C) CuCl\u2082
D) Fe\u2082O\u2083
Answer:<\/strong> A
Explanation:<\/strong> Finely divided Ni is common catalyst for hydrogenation of oils.<\/p>\n\n\n\n

79. In Deacon\u2019s process (manufacture of Cl\u2082), the catalyst is:
<\/mark><\/strong>A) Pt
B) CuCl\u2082
C) Fe
D) Ni
Answer:<\/strong> B
Explanation:<\/strong> CuCl\u2082 catalyzes oxidation of HCl to Cl\u2082.<\/p>\n\n\n\n

80. In catalytic converters of cars, which metals are used?
<\/strong><\/mark>A) Pt, Pd, Rh
B) Fe, Cu
C) Ni, Zn
D) Cr, Mn
Answer:<\/strong> A
Explanation:<\/strong> Pt, Pd, and Rh reduce NOx and oxidize CO and hydrocarbons.<\/p>\n\n\n\n

81. Which catalyst is used for oxidation of SO\u2082 to SO\u2083 in Contact process?
<\/mark><\/strong>A) Pt
B) V\u2082O\u2085
C) Ni
D) Fe
Answer:<\/strong> B
Explanation:<\/strong> Vanadium pentoxide (V\u2082O\u2085) catalyzes SO\u2082 \u2192 SO\u2083.<\/p>\n\n\n\n

82. Ziegler\u2013Natta catalysts are used in:
<\/mark><\/strong>A) Polymerization of alkenes
B) Decomposition of H\u2082O\u2082
C) Hydrolysis of esters
D) Oxidation of NH\u2083
Answer:<\/strong> A
Explanation:<\/strong> Ziegler\u2013Natta catalysts (TiCl\u2084 + AlEt\u2083) polymerize alkenes like ethene, propene.<\/p>\n\n\n\n

83. Which catalyst is used in methanol synthesis from CO + H\u2082?
<\/mark><\/strong>A) Ni
B) Fe
C) Cu\u2013ZnO\u2013Al\u2082O\u2083
D) Pt
Answer:<\/strong> C
Explanation:<\/strong> Methanol synthesis uses Cu\u2013ZnO\u2013Al\u2082O\u2083.<\/p>\n\n\n\n

84. Which catalyst is used in Wacker process (oxidation of ethene to acetaldehyde)?
<\/mark><\/strong>A) PdCl\u2082\u2013CuCl\u2082
B) Ni
C) Pt
D) Fe
Answer:<\/strong> A
Explanation:<\/strong> Wacker process uses PdCl\u2082\u2013CuCl\u2082 as catalysts.<\/p>\n\n\n\n

85. Which is an example of photocatalysis?
<\/mark><\/strong>A) Photosynthesis
B) Decomposition of H\u2082O\u2082 by MnO\u2082
C) Haber process
D) Contact process
Answer:<\/strong> A
Explanation:<\/strong> Photosynthesis is catalyzed by chlorophyll under light \u2192 photocatalysis.<\/p>\n\n\n\n

86. Which catalyst is used in Fischer\u2013Tropsch process (coal \u2192 liquid fuels)?
<\/mark><\/strong>A) Fe or Co
B) Ni
C) Cu
D) Pt
Answer:<\/strong> A
Explanation:<\/strong> Fischer\u2013Tropsch process uses Fe or Co catalysts.<\/p>\n\n\n\n

87. Which is an example of autocatalysis in biology?
<\/mark><\/strong>A) DNA replication
B) Photosynthesis
C) Respiration
D) Hydrolysis of starch
Answer:<\/strong> A
Explanation:<\/strong> DNA replication is autocatalytic because the product (DNA) helps catalyze its own synthesis.<\/p>\n\n\n\n

88. The function of a catalyst in equilibrium reaction is to:
<\/mark><\/strong>A) Change equilibrium constant
B) Increase rate of forward reaction only
C) Increase rate of both forward and backward reactions equally
D) Increase yield of product
Answer:<\/strong> C
Explanation:<\/strong> Catalyst speeds up both directions equally \u2192 equilibrium reached faster, not shifted.<\/p>\n\n\n\n

89. Catalyst increases rate of reaction by:
<\/mark><\/strong>A) Increasing activation energy
B) Decreasing activation energy
C) Increasing free energy
D) Increasing enthalpy
Answer:<\/strong> B
Explanation:<\/strong> Catalyst lowers activation energy by providing alternate pathway.<\/p>\n\n\n\n

90. In Haber process, a catalyst poison is:
<\/mark><\/strong>A) H\u2082S
B) CO\u2082
C) O\u2082
D) H\u2082O
Answer:<\/strong> A
Explanation:<\/strong> H\u2082S poisons Fe catalyst.<\/p>\n\n\n\n

91. The most specific and efficient catalysts are:
<\/mark><\/strong>A) Metals
B) Enzymes
C) Acids
D) Alkalis
Answer:<\/strong> B
Explanation:<\/strong> Enzymes are highly specific biocatalysts.<\/p>\n\n\n\n

92. Which catalyst is used in catalytic cracking in petroleum industry?
<\/mark><\/strong>A) Pt\/Al\u2082O\u2083
B) Ni
C) Fe
D) V\u2082O\u2085
Answer:<\/strong> A
Explanation:<\/strong> Catalytic cracking uses Pt or zeolite catalysts on alumina support.<\/p>\n\n\n\n

93. Which catalyst is used in Haber\u2013Bosch process for NH\u2083?
<\/mark><\/strong>A) Fe + K\u2082O\/Al\u2082O\u2083 promoters
B) Pt\u2013Rh gauze
C) V\u2082O\u2085
D) Ni
Answer:<\/strong> A
Explanation:<\/strong> Haber\u2013Bosch process uses Fe with K\u2082O, Al\u2082O\u2083 promoters.<\/p>\n\n\n\n

94. Which catalyst is used in synthesis of acetic acid from methanol + CO (Monsanto process)?
<\/mark><\/strong>A) RhI\u2082
B) Ni
C) Pt
D) Fe
Answer:<\/strong> A
Explanation:<\/strong> Monsanto process uses Rh catalyst (RhI\u2082(CO)\u2082\u207b complex).<\/p>\n\n\n\n

95. Which catalyst is used in hydrodesulfurization of petroleum?
<\/mark><\/strong>A) Co\u2013Mo\u2013Al\u2082O\u2083
B) Pt
C) Ni
D) V\u2082O\u2085
Answer:<\/strong> A
Explanation:<\/strong> Cobalt\u2013Molybdenum catalyst on alumina support removes sulfur from petroleum.<\/p>\n\n\n\n

96. Which catalyst is used in decomposition of KClO\u2083 to O\u2082?
<\/mark><\/strong>A) MnO\u2082
B) Fe\u2082O\u2083
C) V\u2082O\u2085
D) Ni
Answer:<\/strong> A
Explanation:<\/strong> MnO\u2082 catalyzes KClO\u2083 decomposition to O\u2082.<\/p>\n\n\n\n

97. Which is the main advantage of catalyst in industry?
<\/mark><\/strong>A) Increases cost of production
B) Reduces time and energy required
C) Decreases yield
D) Changes product composition
Answer:<\/strong> B
Explanation:<\/strong> Catalyst lowers energy requirement and speeds up reaction \u2192 economical.<\/p>\n\n\n\n

98. Which is a heterogeneous catalyst in Haber process?
<\/mark><\/strong>A) Fe solid
B) NH\u2083
C) H\u2082
D) N\u2082
Answer:<\/strong> A
Explanation:<\/strong> Fe (solid) acts as heterogeneous catalyst with gaseous reactants.<\/p>\n\n\n\n

99. Which is the role of promoters like K\u2082O in Haber process?
<\/mark><\/strong>A) Acts as poison
B) Increases activity of Fe catalyst
C) Decreases rate
D) Absorbs NH\u2083
Answer:<\/strong> B
Explanation:<\/strong> Promoters increase efficiency of main catalyst.<\/p>\n\n\n\n

100. Which statement about catalysts is correct?
<\/mark><\/strong>A) Catalyst alters equilibrium constant
B) Catalyst is consumed in reaction
C) Catalyst lowers activation energy
D) Catalyst changes \u0394H of reaction
Answer:<\/strong> C
Explanation:<\/strong> Catalyst provides alternative pathway with lower activation energy, but does not change \u0394H or equilibrium constant.<\/p>\n","protected":false},"excerpt":{"rendered":"

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