The Bihar Board Class 12 Chemistry Exam is a vital part of the BSEB curriculum. It requires conceptual clarity, deep understanding, and rigorous practice. Chemistry includes Physical Chemistry, Inorganic Chemistry, and Organic Chemistry, and objective questions from all these parts carry high marks in the board exam.
Practicing objective-type questions with options helps students revise topics quickly and build confidence before exams. These questions are based on the latest Bihar Board syllabus and cover every important chapter from Solutions, Electrochemistry, Chemical Kinetics, Surface Chemistry, Coordination Compounds, Organic Compounds, and Biomolecules.
Below are 75 important objective questions with options and answers that will help you prepare effectively for your upcoming examination.
Bihar Board Class 12 Chemistry Objective Questions with Option | 75 Important MCQs with Answers
Bihar Board Class 12 Chemistry Objective Questions with Option
1. The number of moles in 22 grams of CO₂ is —
A) 0.25 mol
B) 0.5 mol
C) 1 mol
D) 2 mol
Answer: B) 0.5 mol
2. The molar mass of water (H₂O) is —
A) 16 g/mol
B) 18 g/mol
C) 20 g/mol
D) 10 g/mol
Answer: B) 18 g/mol
3. Avogadro’s number is —
A) 3.03 × 10²³
B) 6.022 × 10²³
C) 9.01 × 10²³
D) 1.66 × 10⁻²⁴
Answer: B) 6.022 × 10²³
4. The oxidation number of nitrogen in NH₃ is —
A) +3
B) -3
C) +1
D) 0
Answer: B) -3
5. The chemical formula of bleaching powder is —
A) CaCO₃
B) CaOCl₂
C) Ca(OH)₂
D) CaCl₂
Answer: B) CaOCl₂
6. The shape of H₂O molecule is —
A) Linear
B) Tetrahedral
C) Bent
D) Trigonal planar
Answer: C) Bent
7. The oxidation involves —
A) Gain of hydrogen
B) Loss of oxygen
C) Loss of electrons
D) Gain of electrons
Answer: C) Loss of electrons
8. The number of protons in an atom of oxygen is —
A) 6
B) 8
C) 10
D) 12
Answer: B) 8
9. The pH of pure water at 25°C is —
A) 6
B) 7
C) 8
D) 9
Answer: B) 7
10. The IUPAC name of CH₃COOH is —
A) Methanoic acid
B) Ethanoic acid
C) Propanoic acid
D) Butanoic acid
Answer: B) Ethanoic acid
11. Which gas is used in Haber’s process?
A) Oxygen
B) Nitrogen
C) Hydrogen
D) Both B and C
Answer: D) Both B and C
12. The atomic number of sodium is —
A) 10
B) 11
C) 12
D) 13
Answer: B) 11
13. The molecular formula of glucose is —
A) C₂H₅OH
B) C₆H₁₂O₆
C) CH₃COOH
D) C₂H₄
Answer: B) C₆H₁₂O₆
14. The hardest natural substance is —
A) Iron
B) Graphite
C) Diamond
D) Quartz
Answer: C) Diamond
15. The atomic number of carbon is —
A) 5
B) 6
C) 7
D) 8
Answer: B) 6
16. Which of the following is a strong acid?
A) CH₃COOH
B) H₂SO₄
C) NH₄OH
D) H₂O
Answer: B) H₂SO₄
17. The chemical name of baking soda is —
A) Na₂CO₃
B) NaHCO₃
C) NaOH
D) NaCl
Answer: B) NaHCO₃
18. Which bond is present in H₂ molecule?
A) Ionic bond
B) Covalent bond
C) Metallic bond
D) Hydrogen bond
Answer: B) Covalent bond
19. Which of the following is an amphoteric oxide?
A) Al₂O₃
B) CaO
C) Na₂O
D) CO₂
Answer: A) Al₂O₃
20. Which of the following is a noble gas?
A) Nitrogen
B) Argon
C) Oxygen
D) Hydrogen
Answer: B) Argon
21. What is the chemical symbol of potassium?
A) P
B) Pt
C) K
D) Po
Answer: C) K
22. Which of the following is used as a refrigerant?
A) NH₃
B) SO₂
C) CO₂
D) O₂
Answer: A) NH₃
23. The metal used in the extraction of copper is —
A) Iron
B) Zinc
C) Lead
D) Aluminium
Answer: B) Zinc
24. The functional group in alcohol is —
A) -CHO
B) -COOH
C) -OH
D) -CO-
Answer: C) -OH
25. The catalyst used in the contact process is —
A) Fe
B) V₂O₅
C) MnO₂
D) Pt
Answer: B) V₂O₅
26. Which is the lightest gas?
A) Helium
B) Hydrogen
C) Oxygen
D) Methane
Answer: B) Hydrogen
27. The atomic number of chlorine is —
A) 17
B) 18
C) 19
D) 20
Answer: A) 17
28. Which law states that equal volumes of gases contain equal number of molecules?
A) Boyle’s law
B) Charles’s law
C) Avogadro’s law
D) Dalton’s law
Answer: C) Avogadro’s law
29. The color of CuSO₄·5H₂O crystals is —
A) White
B) Blue
C) Green
D) Yellow
Answer: B) Blue
30. The gas used in soda water is —
A) CO₂
B) O₂
C) H₂
D) N₂
Answer: A) CO₂
31. Which of the following is a reducing agent?
A) KMnO₄
B) H₂
C) O₂
D) Cl₂
Answer: B) H₂
32. What is the oxidation number of Fe in Fe₂O₃?
A) +2
B) +3
C) +4
D) +6
Answer: B) +3
33. Which of the following is an organic compound?
A) NaCl
B) CH₄
C) K₂SO₄
D) CaCO₃
Answer: B) CH₄
34. The compound containing carbon and hydrogen only is called —
A) Hydrocarbon
B) Carbohydrate
C) Protein
D) Alcohol
Answer: A) Hydrocarbon
35. The catalyst used in the Haber process is —
A) Nickel
B) Iron
C) Platinum
D) Copper
Answer: B) Iron
36. The main ore of aluminium is —
A) Bauxite
B) Hematite
C) Galena
D) Magnetite
Answer: A) Bauxite
37. The process of coating zinc on iron is called —
A) Rusting
B) Galvanization
C) Electrolysis
D) Amalgamation
Answer: B) Galvanization
38. The element present in chlorophyll is —
A) Iron
B) Magnesium
C) Zinc
D) Copper
Answer: B) Magnesium
39. The unit of molarity is —
A) mol/L
B) g/L
C) mol/kg
D) L/mol
Answer: A) mol/L
40. The boiling point of water is —
A) 0°C
B) 50°C
C) 100°C
D) 212°C
Answer: C) 100°C
41. The pH of a neutral solution is —
A) 0
B) 7
C) 14
D) 2
Answer: B) 7
42. The process of conversion of solid into gas is —
A) Fusion
B) Sublimation
C) Condensation
D) Evaporation
Answer: B) Sublimation
43. The functional group in aldehyde is —
A) -COOH
B) -CHO
C) -CO-
D) -OH
Answer: B) -CHO
44. The molecular formula of ethanol is —
A) CH₃CHO
B) C₂H₅OH
C) CH₃OH
D) C₂H₆
Answer: B) C₂H₅OH
45. Which one is a noble gas?
A) Neon
B) Hydrogen
C) Nitrogen
D) Oxygen
Answer: A) Neon
46. The element which forms the highest number of compounds is —
A) Hydrogen
B) Oxygen
C) Carbon
D) Nitrogen
Answer: C) Carbon
47. The process of electrolysis of water gives —
A) O₂ only
B) H₂ only
C) H₂ and O₂
D) CO₂
Answer: C) H₂ and O₂
48. Which of the following is a polymer?
A) Starch
B) NaCl
C) H₂O
D) CO₂
Answer: A) Starch
49. The catalyst used in hydrogenation of oils is —
A) Nickel
B) Iron
C) Copper
D) Platinum
Answer: A) Nickel
50. Which metal is liquid at room temperature?
A) Iron
B) Sodium
C) Mercury
D) Aluminium
Answer: C) Mercury
51. Which acid is present in lemon?
A) Acetic acid
B) Citric acid
C) Tartaric acid
D) Oxalic acid
Answer: B) Citric acid
52. The molecular formula of methane is —
A) CH₄
B) C₂H₆
C) CH₃OH
D) C₂H₄
Answer: A) CH₄
53. Which among the following has maximum electronegativity?
A) Oxygen
B) Fluorine
C) Nitrogen
D) Chlorine
Answer: B) Fluorine
54. Which acid is used in car batteries?
A) Hydrochloric acid
B) Nitric acid
C) Sulphuric acid
D) Acetic acid
Answer: C) Sulphuric acid
55. The atomic number of calcium is —
A) 18
B) 19
C) 20
D) 21
Answer: C) 20
56. The SI unit of energy is —
A) Watt
B) Joule
C) Newton
D) Pascal
Answer: B) Joule
57. The process of rusting involves —
A) Oxidation
B) Reduction
C) Sublimation
D) Neutralization
Answer: A) Oxidation
58. The color of iodine vapour is —
A) Red
B) Violet
C) Blue
D) Yellow
Answer: B) Violet
59. The neutralization of acid and base produces —
A) Salt and Water
B) Salt only
C) Water only
D) Hydrogen gas
Answer: A) Salt and Water
60. The valency of nitrogen in NH₃ is —
A) 1
B) 2
C) 3
D) 4
Answer: C) 3
61. The element used in making semiconductor devices is —
A) Carbon
B) Silicon
C) Iron
D) Copper
Answer: B) Silicon
62. Which of the following is used in matchsticks?
A) Sulphur
B) Phosphorus
C) Chlorine
D) Potassium
Answer: B) Phosphorus
63. The chemical name of quicklime is —
A) CaCO₃
B) CaO
C) Ca(OH)₂
D) CaCl₂
Answer: B) CaO
64. The process of heating an ore in the absence of air is called —
A) Calcination
B) Roasting
C) Reduction
D) Oxidation
Answer: A) Calcination
65. The color of Cu²⁺ ion is —
A) Green
B) Blue
C) Red
D) Yellow
Answer: B) Blue
66. The main constituent of air is —
A) O₂
B) N₂
C) CO₂
D) H₂
Answer: B) N₂
67. The metal present in hemoglobin is —
A) Iron
B) Copper
C) Zinc
D) Calcium
Answer: A) Iron
68. The process of separating mixtures using electricity is called —
A) Electrolysis
B) Distillation
C) Filtration
D) Sublimation
Answer: A) Electrolysis
69. The molecular mass of NaCl is —
A) 56.5
B) 58.5
C) 60.5
D) 64.5
Answer: B) 58.5
70. Which element has the symbol ‘Fe’?
A) Fluorine
B) Iron
C) Ferric
D) Francium
Answer: B) Iron
71. The acid present in vinegar is
—
A) Acetic acid
B) Citric acid
C) Formic acid
D) Oxalic acid
Answer: A) Acetic acid
72. The compound used for softening hard water is —
A) Washing soda
B) Bleaching powder
C) Common salt
D) Vinegar
Answer: A) Washing soda
73. The number of neutrons in carbon-12 is —
A) 6
B) 12
C) 8
D) 4
Answer: A) 6
74. Which of the following has a triple bond?
A) N₂
B) O₂
C) H₂
D) Cl₂
Answer: A) N₂
75. Which of the following is an alloy?
A) Brass
B) Sodium
C) Zinc
D) Iron
Answer: A) Brass
Conclusion-Bihar Board Class 12 Chemistry Objective Questions
These Bihar Board Class 12 Chemistry Objective Questions with Options are designed according to the latest syllabus to help students prepare efficiently for the 2025 board exams. Practicing them regularly will improve your accuracy, conceptual clarity, and speed — key factors to score full marks in the Chemistry objective section.
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