If you are preparing for the Bihar Board Class 12 Chemistry 2026 Exam, then practicing objective questions is the best way to achieve a strong score. Chemistry in Class 12 consists of Physical, Inorganic, and Organic parts, and objective questions from all these sections are asked in the board exam.
In this post, we have listed the top 75 most important Chemistry objective questions with options and correct answers, based on the latest Bihar Board syllabus and NCERT textbooks. Each question is carefully selected to strengthen your preparation.
Bihar Board Class 12 Chemistry 75 Objective Question with Option and Answer 2026
Bihar Board Class 12 Chemistry 75 Objective Question with Option and Answer
Q1. The molar mass of water is:
a) 16 g/mol
b) 18 g/mol
c) 20 g/mol
d) 22 g/mol
Answer: 18 g/mol
Q2. The oxidation number of sulfur in H₂SO₄ is:
a) +4
b) +6
c) +2
d) 0
Answer: +6
Q3. Which gas is known as laughing gas?
a) CO₂
b) N₂O
c) NO₂
d) SO₂
Answer: N₂O
Q4. The process of conversion of solid directly into gas is called:
a) Condensation
b) Sublimation
c) Evaporation
d) Fusion
Answer: Sublimation
Q5. Which of the following is a noble gas?
a) Nitrogen
b) Oxygen
c) Argon
d) Carbon dioxide
Answer: Argon
Q6. The atomic number of oxygen is:
a) 6
b) 8
c) 10
d) 12
Answer: 8
Q7. The chemical formula of washing soda is:
a) Na₂CO₃·10H₂O
b) NaHCO₃
c) NaOH
d) NaCl
Answer: Na₂CO₃·10H₂O
Q8. The gas evolved during fermentation is:
a) Oxygen
b) Nitrogen
c) Carbon dioxide
d) Hydrogen
Answer: Carbon dioxide
Q9. Which of the following is an amphoteric oxide?
a) CO₂
b) Al₂O₃
c) Na₂O
d) SO₂
Answer: Al₂O₃
Q10. The pH of neutral solution at 25°C is:
a) 0
b) 1
c) 7
d) 14
Answer: 7
Q11. The main ore of aluminium is:
a) Magnetite
b) Bauxite
c) Hematite
d) Galena
Answer: Bauxite
Q12. The element having highest electronegativity is:
a) Fluorine
b) Chlorine
c) Oxygen
d) Nitrogen
Answer: Fluorine
Q13. The number of valence electrons in carbon is:
a) 2
b) 4
c) 6
d) 8
Answer: 4
Q14. The unit of rate constant in first order reaction is:
a) mol/L·s
b) s⁻¹
c) L/mol·s
d) mol²/L²·s
Answer: s⁻¹
Q15. Which of the following is a reducing agent?
a) KMnO₄
b) H₂S
c) HNO₃
d) O₃
Answer: H₂S
Q16. The common name of calcium carbonate is:
a) Baking soda
b) Chalk
c) Washing soda
d) Quick lime
Answer: Chalk
Q17. Which of the following is an organic acid?
a) H₂SO₄
b) HCl
c) CH₃COOH
d) HNO₃
Answer: CH₃COOH
Q18. The functional group in alcohol is:
a) -COOH
b) -OH
c) -CHO
d) -CO-
Answer: -OH
Q19. The compound used in photography is:
a) NaCl
b) AgBr
c) KCl
d) NaBr
Answer: AgBr
Q20. The first law of thermodynamics is based on:
a) Conservation of mass
b) Conservation of energy
c) Conservation of charge
d) Conservation of volume
Answer: Conservation of energy
Q21. Avogadro’s number is:
a) 6.022 × 10²³
b) 3.14
c) 1.602 × 10⁻¹⁹
d) 9.8
Answer: 6.022 × 10²³
Q22. The catalyst used in the Haber process is:
a) Nickel
b) Iron
c) Platinum
d) Vanadium oxide
Answer: Iron
Q23. The oxidation number of chlorine in NaClO₃ is:
a) +3
b) +5
c) +1
d) +7
Answer: +5
Q24. Which of the following is a colloid?
a) Sugar solution
b) Milk
c) Salt solution
d) Water
Answer: Milk
Q25. The gas used in electric bulbs is:
a) Oxygen
b) Nitrogen
c) Argon
d) Hydrogen
Answer: Argon
Q26. The rate of reaction depends on:
a) Temperature
b) Concentration
c) Catalyst
d) All of these
Answer: All of these
Q27. The chemical formula of bleaching powder is:
a) CaOCl₂
b) CaCl₂
c) Ca(OH)₂
d) CaCO₃
Answer: CaOCl₂
Q28. pH value of lemon juice is around:
a) 1
b) 2
c) 7
d) 10
Answer: 2
Q29. The color of CuSO₄·5H₂O is:
a) White
b) Blue
c) Green
d) Red
Answer: Blue
Q30. The purest form of carbon is:
a) Charcoal
b) Graphite
c) Diamond
d) Coke
Answer: Diamond
Q31. The compound responsible for acid rain is:
a) CO₂
b) SO₂
c) O₂
d) CH₄
Answer: SO₂
Q32. The pH of human blood is approximately:
a) 5
b) 7.4
c) 9
d) 6
Answer: 7.4
Q33. The main component of vinegar is:
a) Formic acid
b) Acetic acid
c) Citric acid
d) Oxalic acid
Answer: Acetic acid
Q34. The bond present in H₂ molecule is:
a) Ionic
b) Covalent
c) Metallic
d) Coordinate
Answer: Covalent
Q35. Which of the following is an allotrope of carbon?
a) Graphite
b) Diamond
c) Fullerene
d) All of these
Answer: All of these
Q36. Which metal is liquid at room temperature?
a) Sodium
b) Mercury
c) Iron
d) Lead
Answer: Mercury
Q37. The hardest natural substance is:
a) Iron
b) Graphite
c) Diamond
d) Quartz
Answer: Diamond
Q38. The main gas responsible for greenhouse effect is:
a) O₂
b) CO₂
c) N₂
d) H₂
Answer: CO₂
Q39. The atomic number of sodium is:
a) 10
b) 11
c) 12
d) 13
Answer: 11
Q40. Which acid is used in car batteries?
a) Hydrochloric acid
b) Sulphuric acid
c) Nitric acid
d) Phosphoric acid
Answer: Sulphuric acid
Q41. The main constituent of air is:
a) Oxygen
b) Nitrogen
c) Carbon dioxide
d) Hydrogen
Answer: Nitrogen
Q42. The SI unit of pressure is:
a) Pascal
b) Bar
c) Torr
d) Atmosphere
Answer: Pascal
Q43. Which of the following is a strong electrolyte?
a) Glucose
b) Acetic acid
c) NaCl
d) Urea
Answer: NaCl
Q44. The valency of nitrogen in ammonia (NH₃) is:
a) 1
b) 2
c) 3
d) 5
Answer: 3
Q45. The process of rusting involves:
a) Oxidation
b) Reduction
c) Both
d) None
Answer: Oxidation
Q46. Which of the following is an alkali metal?
a) Mg
b) Na
c) Al
d) Cu
Answer: Na
Q47. The chemical symbol of gold is:
a) Ag
b) Au
c) Gd
d) Go
Answer: Au
Q48. Which of the following is used as a moderator in nuclear reactors?
a) Heavy water
b) Sulphur
c) Nitrogen
d) Argon
Answer: Heavy water
Q49. The gas which turns lime water milky is:
a) SO₂
b) CO₂
c) CO
d) O₂
Answer: CO₂
Q50. Which of the following is an endothermic reaction?
a) Combustion
b) Photosynthesis
c) Respiration
d) Neutralization
Answer: Photosynthesis
Q51. Atomic number of chlorine is:
a) 16
b) 17
c) 18
d) 19
Answer: 17
Q52. The element with atomic number 20 is:
a) Sodium
b) Calcium
c) Potassium
d) Magnesium
Answer: Calcium
Q53. Formula of quicklime is:
a) CaO
b) CaCO₃
c) Ca(OH)₂
d) CaSO₄
Answer: CaO
Q54. The number of moles in 22.4 L of gas at STP is:
a) 0.5
b) 1
c) 2
d) 3
Answer: 1
Q55. The main gas found in biogas is:
a) CO₂
b) CH₄
c) O₂
d) N₂
Answer: CH₄
Q56. The atomic number of carbon is:
a) 4
b) 6
c) 8
d) 10
Answer: 6
Q57. Which acid is known as aqua fortis?
a) HNO₃
b) HCl
c) H₂SO₄
d) H₃PO₄
Answer: HNO₃
Q58. Which metal is extracted from bauxite?
a) Iron
b) Aluminium
c) Copper
d) Lead
Answer: Aluminium
Q59. Vinegar is a solution of:
a) Acetic acid
b) Citric acid
c) Formic acid
d) Sulphuric acid
Answer: Acetic acid
Q60. The gas used in fire extinguishers is:
a) CO₂
b) O₂
c) N₂
d) H₂
Answer: CO₂
Q61. The atomic number of fluorine is:
a) 7
b) 8
c) 9
d) 10
Answer: 9
Q62. The chemical symbol of iron is:
a) Ir
b) Fe
c) In
d) I
Answer: Fe
Q63. The pH of pure water is:
a) 5
b) 6
c) 7
d) 8
Answer: 7
Q64. The main ore of iron is:
a) Bauxite
b) Hematite
c) Galena
d) Zincite
Answer: Hematite
Q65. The functional group of aldehyde is:
a) -COOH
b) -CHO
c) -OH
d) -CO-
Answer: -CHO
Q66. Which of the following is an acidic oxide?
a) CO₂
b) CaO
c) Na₂O
d) MgO
Answer: CO₂
Q67. The molecular mass of CO₂ is:
a) 42
b) 44
c) 46
d) 48
Answer: 44
Q68. The catalyst used in contact process is:
a) Fe
b) Pt
c) V₂O₅
d) Ni
Answer: V₂O₅
Q69. The atomic number of neon is:
a) 9
b) 10
c) 11
d) 12
Answer: 10
Q70. The purest form of iron is:
a) Wrought iron
b) Pig iron
c) Cast iron
d) None
Answer: Wrought iron
Q71. The process of electrolysis of water gives:
a) H₂ and O₂
b) H₂ and N₂
c) H₂ and CO₂
d) H₂ and SO₂
Answer: H₂ and O₂
Q72. The gas which supports combustion is:
a) CO₂
b) H₂
c) O₂
d) N₂
Answer: O₂
Q73. The formula of gypsum is:
a) CaSO₄·2H₂O
b) CaCO₃
c) CaO
d) Ca(OH)₂
Answer: CaSO₄·2H₂O
Q74. The chemical name of baking soda is:
a) Sodium carbonate
b) Sodium bicarbonate
c) Sodium chloride
d) Sodium hydroxide
Answer: Sodium bicarbonate
Q75. The metal used in making wires is:
a) Mercury
b) Copper
c) Iron
d) Aluminium
Answer: Copper
Top 10 FAQs – Bihar Board Class 12 Chemistry 2026
Q1. How many objective questions are there in Chemistry exam?
Around 35–40 objective questions are asked in the paper.
Q2. What is the total marks distribution?
Theory: 70 marks, Practical: 30 marks.
Q3. Are numerical questions included?
Yes, numerical-based MCQs come from Physical Chemistry chapters.
Q4. Is NCERT enough for the board exam?
Yes, NCERT is completely sufficient for board preparation.
Q5. Which chapters are most important?
Electrochemistry, p-block, Chemical Kinetics, Coordination Compounds.
Q6. Can I score full marks in Chemistry?
Yes, by practicing objective questions daily and revising all formulas.
Q7. How many hours should I study Chemistry daily?
At least 2 hours of focused study with MCQ practice.
Q8. Is Organic Chemistry easy?
Yes, if you learn mechanisms and reactions regularly.
Q9. What is the exam duration?
The theory exam is of 3 hours.
Q10. How can I score 90+ marks in Chemistry?
Focus on NCERT, practice objective questions, and revise chemical reactions.
Conclusion-Bihar Board Class 12 Chemistry 75 Objective
This blog on Bihar Board Class 12 Chemistry 75 Objective Question with Option and Answer covers all important concepts from the latest syllabus. Regular practice of these MCQs will strengthen your understanding and help you perform well in the 2026 Chemistry exam.
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