Bihar Board Class 12 Chemistry Guess Questions 2025
Bihar Board Chemistry Notes, MCQs, PYQs, Sample Papers
Bihar Board Cass 12 Chemistry Important Questions
Subjective Questions
Section: B
Short Answer Type Questions
20 question to be asked answer any 10 questions. Each question carries 2 marks.
1. Define isomerism.2. What is a catalyst ?
3. State Raoult's Law.
4. What are the types of chemical bonds ?
5. Define pH and its significance.
6. What is the difference between an alkane and an alkene ?
7. Explain the term 'electrolyte and electrolytic solution'.
8. What is the principle of chromatography ?
9. Define molarity and molality.
10. What is a buffer solution ?
11. State the law of conservation of mass.
12. What is the difference between oxidation and reduction ?
13. Define hybridization with an example.
14. What are the main characteristics of acids and bases ?
15. Explain the term 'enthalpy'.
16. What is a redox reaction? Give an example.
17. Define coordination compounds and give an example.
18. What is the role of enzymes in biochemical reactions?
19. What are primary, secondary, and tertiary alcohols ?
20. Explain the concept of atomic radius in periodic trends.
21. What is unit cell?
22. Explain Zinc oxide is white when cold but yellow when hot.
23. What do you understand by relative lowering of vapour pressure ?
24. What is reverse osmosis ?
25. What is Azeotropic mixture ?
26. What is Arrhenius equation ?
27. Differentiate between adsorption and absorption.
28. What is homogeneous catalysis ? Give examples.
29. What is dialysis ?
30. Write names and chemical formulae of two ores of Aluminium.
31. What is the structure of SO42- ?
32. Write down electronic configuration of the following:
(i) Cr3+ (z=24) (ii) Zn2+ (z=30)
33. Write structural formula of EDTA.
34. What is elimination reaction ?
35. What happens when phenol is heated with zinc powder ?
36. What is Resenmund’s reaction ?
37. Write structural formula of the following:
(i) Tartaric acid (ii) Isobutyric acid
38. How would you convert ethylamine to ethylalcohol ?
39. What are Nucleic Acids ?
40. What are macromolecules ?
41. How many tetrahedral and octahedral voids are there in closed packing of N spheres?
42. What is Henry’s law of solubility ?
43. Define Osmosis and Osmotic pressure.
44. What is specific conductance ?
45. What do you understand by molecularity of a reaction ?
46. What do you understand by physical and chemical adsorption?
47. Write the name and chemical formula of two chief ores of Zinc.
48. Write the formula and structure of pyrophosphoric acid.
49. Write two uses of Ozone.
50. Arrange HF, HCl, HBr and HI in the increasing order of their acidic strength.
51. What are preservatives of food ? Give examples.
52. Write one use of the following:
(i) Paracetamol (i) Tincture of iodine
53. Amino acids are amphoteric. Explain.
54. Write structural formulae of the following compounds:
(i) N-Ethylethanamine (ii) N, N- Dimethylmethanamine
55. What is Hell Volhard Zelinsky (HVZ) reaction ?
56. Write the name of two reagents which is capable of converting keto (C=O) group to methylene (CH2) group.
57. Write the names and formulae of two compounds which are obtained by the polymerisation of Acetaldehyde.
58. What is power alcohol ? Write its uses ?
59. What is Markownikoff’s rule ?
60. What is electrochemical cell? Explain with one example.
61. Discuss electrochemical principle about rusting of iron.
62. Explain in brief electro refining of metals.
63. How would you convert ethylalcohol into chloroform?
64. What do you mean by Tranquilizers?
65. Write short note on Bakelite.
66. Discuss the structure of [NiCl4]2- with the help of Valence Bond Theory (VBT).
67. How would you obtain Acetone from Acetic acid?
68. Formic acid behaves both as an aldehyde and as an acid. Explain.
69. How would you obtain phenol from aniline ?
70. Which bond is responsible for the stability of -helix structure?
71. Discuss the reaction of Acetaldehyde and HCN in acidic medium.
72. What do you mean by the rate constant of a chemical reaction?
73. What are colligative properties? Write names of colligative properties.
74. What is Van't Hoff factor?
75. What happens when ethylamine is heated with HgCl2 in the presence of CS2?
76. Write two use of DNA finger printing.
77. Explain ideal and non-ideal solution.
78. What do you mean by a Primary cell ?
79. What do you mean by order of reaction ?
80. State and explain Faraday's 2nd law of electrolysis.
81. Write the name and chemical composition of one important ore of each of Aluminium and copper.
82. Name two Vitamins and their deficiency diseases.
83. Define standard elecrode potential.
84. Write the structural formulae of the following:
(i) 2-Butanol
(ii) Ethyl acetate
85. What is Tyndall effect? Explain.
86. How would you convert the following ?
(i) Formc Acid to Formaldehyde
(ii) Benzene to Aniline
87. Explain, why the valency of inert gases is zero?
88. What is carbocation ? Explain.
89. Which one is stronger acid, HF or Hcl? why?
90. Nomenclature 91. What is molal elevation constant? How is it related to molarity of a solution ?
92. What is peptization ?
93. What is sorption ? Give examples.
94. What do you understand point defect ?
95. What happened when benzene reacts with ethyl bromide in the presence of anhydrous AlBr3 ? Write equation.
96. Explain the difference between double salt and coordination compounds.
97. What are preservatives.
98. What is denaturation of protein ?
99. What are isotonic solution ?
100. Discuss the cleansing action of soap.
101. How metals are refined by bassemerization ?
102. What is rducing sugar ?
Subjective Questions
Section: C
Long Answer Type Questions
6 question to be asked answer any 3 questions. Each question carries 5 marks.
1. Explain the process of electrolysis with Faraday's laws, including practical applications.2. Discuss the Haber process for ammonia production, detailing its significance in industry and agriculture.
3. Describe the structure and bonding in benzene, including resonance structures and hybridization concept.
4. Differentiate between endothermic and exothermic reactions with examples and energy diagrams for both types of reactions.
5. Explain the concept of chemical kinetics, including factors affecting reaction rates and examples of each factor's influence on rate constants.
6. Describe the principles of thermodynamics as applied to chemical reactions, including enthalpy changes and Gibbs free energy calculations for spontaneous processes.
7. What do you understand by Primary and Secondary cells ? Explain by giving one examples of each.
8. What is first order reaction? Give two examples of first order reaction. Obtain an experssion for the rate constant of a first order reaction.
9. Write structural formulae and basicity of the following:
(i) H3PO3 (ii) H3PO4 (iii) H3PO2
10. What is Lanthanide contraction ? What are its consequences ?
11. Starting from ethanoic acid how would you obtain the following ?
(i) Acetone (ii) Methane
12. Differentiate between DNA and RNA.
13. What happens when-
(i) Chlorine gas reacts with NaOH ?
(ii) Nitric acid reacts with Zn or Cu at different concentrations ?
14. (i) Discuss the principle of extraction of Zinc metal from Zinc blende ore.
(ii) How does Zn react with H2SO4 ?
15. What are Carbohydrates ? How are they classified?
16. (i) Differentiate between Methanoic acid and Ethanoic acid.
(ii) How Acetic acid is obtained from Methyl cyanide ?
17. What do you understand by Depression in Freezing point ? Obtain a mathematical expression to determine the molecular weight of a solute with the help of Depression in Freezing point.
18. What are electrode potential and standard electrode potential ? Discuss the effect of concentration of a solution on standard electrode potential.
19. Define Osmosis and Osmotic pressure. How the molecular mass of a non volatile and non-electrolyte solute is determined with the help of Osmotic pressure measurement?
20. What are the main sources of Iodine? How is Iodine extracted from sea weeds?
21. Give two important ores of Iron. Write in short the process of extraction from its ore.
22. What happens when
(i) Dry calcium formate is strongly heated ?
(ii) Chloroform reacts with air in the presence of sunlight ?
23. Discuss primary structure of protein.
24. How is sulphuric acid manufactured by Lead Chamber process ?
25. What are Carbohydrates? How are they classified?
26. What happens when ?
(i) Calcium acetate is heated.
(ii) Ethyl amine reacts with HNO2.
(iii) Acetylene is passed through red hot copper tube?
(iv) Benzene is heated with a mixture of concentrated HNO3 and H2SO4.
(v) Ethyl alcohol is oxidised.
27. Discuss the following:
A. Kolbe's reaction
B. Carbylamine reaction
28. What is the effect of temperature on reaction rate ? What is Arrhenius equation ?
29. (i) Explain the principle of manufacturing of sulphuric acid by contct process.
(ii) Write the reaction of concentrated sulphusric acid with oxalic acid.
30. Compounds of transition elements are paramagnetic and colored explain.
31. How would you distinguish between the following compounds by chemical tests
(i) Formaldehyde and Acetaldehyde
(ii) Acetaldehyde and Acetone.