Chemistry in Class 12 plays a very important role for students of the Bihar School Examination Board (BSEB). It not only affects board exam results but also forms the foundation for competitive exams like JEE, NEET, and other entrance tests. To score high marks, students must have a strong grasp of key concepts, formulas, and short notes for every chapter for the Bihar Board Class 12th Chemistry Short Notes and Formulas 2025In this post, we have provided Bihar Board Class 12th Chemistry Short Notes and Formulas 2025-2026 in a simplified manner to make revision easy.
Bihar Board Class 12th Chemistry Short Notes and Formulas 2025-2026
Chapter-Wise Chemistry Short Notes and Formulas
1. Solid State
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Types of Solids: Crystalline and Amorphous
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Unit Cell: Simple cubic, BCC, FCC
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Packing Efficiency:
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SC = 52%
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BCC = 68%
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FCC = 74%
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Density Formula:
Density=Z×Ma3×NA\text{Density} = \frac{Z \times M}{a^3 \times N_A}
Where, Z = Number of atoms per unit cell, M = Molar mass, a = Edge length, NAN_A = Avogadro number
2. Solutions
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Molarity (M):
M=moles of solutevolume of solution in litersM = \frac{\text{moles of solute}}{\text{volume of solution in liters}}
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Molality (m):
m=moles of solutemass of solvent in kgm = \frac{\text{moles of solute}}{\text{mass of solvent in kg}}
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Raoult’s Law: PA=XAPA0P_A = X_A P^0_A
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Colligative Properties:
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Relative lowering of vapor pressure
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Elevation of boiling point: ΔTb=Kb×m\Delta T_b = K_b \times m
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Depression of freezing point: ΔTf=Kf×m\Delta T_f = K_f \times m
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Osmotic pressure: π=CRT\pi = CRT
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3. Electrochemistry
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Ohm’s Law: V=IRV = IR
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Cell Potential:
Ecell=Ecathode0−Eanode0E_{cell} = E^0_{cathode} – E^0_{anode}
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Nernst Equation:
E=E0−0.0591nlogQE = E^0 – \frac{0.0591}{n} \log Q
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Faraday’s Laws of Electrolysis:
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1st Law: Mass deposited ∝\propto quantity of electricity
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2nd Law: Equivalent mass deposited is proportional
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4. Chemical Kinetics
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Rate of Reaction:
Rate=k[A]m[B]nRate = k [A]^m [B]^n
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Half-Life of First Order Reaction:
t1/2=0.693kt_{1/2} = \frac{0.693}{k}
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Arrhenius Equation:
k=Ae−EaRTk = A e^{-\frac{E_a}{RT}}
5. Surface Chemistry
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Adsorption: Adhesion of molecules on surface
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Freundlich Adsorption Isotherm:
x/m=kP1/nx/m = kP^{1/n}
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Catalysis: Homogeneous and Heterogeneous
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Colloids: Tyndall effect, Brownian motion, Coagulation
6. p-Block Elements
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Group 15 (N, P, As, Sb, Bi): Oxidation states −3 to +5
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Group 16 (O, S, Se, Te, Po): Show allotropy (O₂, O₃, S₈)
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Important Compounds:
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Ammonia (NH₃), Nitric Acid (HNO₃), Sulphuric Acid (H₂SO₄)
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7. d-Block Elements
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Transition Metals: Variable oxidation states, colored compounds, catalytic activity
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Important Complexes:
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[Fe(CN)₆]³⁻ (Ferricyanide)
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[Fe(CN)₆]⁴⁻ (Ferrocyanide)
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8. Coordination Compounds
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Werner’s Theory: Primary and secondary valencies
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IUPAC Nomenclature: [Co(NH₃)₆]Cl₃ → Hexaamminecobalt(III) chloride
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Isomerism: Linkage, Coordination, Geometrical, Optical
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Stability Constant: K = [ML][M][L]\frac{[ML]}{[M][L]}
9. Haloalkanes and Haloarenes
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General Formula: RX
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Reactions:
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Nucleophilic substitution (SN1, SN2)
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Elimination reactions
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10. Alcohols, Phenols and Ethers
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Alcohol Oxidation: Primary → Aldehyde → Acid
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Phenol Reactions: Electrophilic substitution (Bromination, Nitration)
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Ethers: Williamson’s synthesis
11. Aldehydes, Ketones and Carboxylic Acids
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General Formula:
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Aldehyde: R-CHO
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Ketone: R-CO-R
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Tests: Fehling’s Test, Tollen’s Test
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Carboxylic Acid: Acidic nature due to resonance
12. Amines
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Classification: Primary, Secondary, Tertiary
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Basicity Order: Aliphatic > Ammonia > Aromatic
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Hofmann Bromamide Reaction: RCONH₂ → RNH₂
13. Biomolecules
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Carbohydrates: Monosaccharides (Glucose), Disaccharides (Sucrose), Polysaccharides (Starch)
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Proteins: Made of amino acids, peptide bond
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Vitamins: Water soluble (B, C), Fat soluble (A, D, E, K)
14. Polymers
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Addition Polymers: Polyethylene, PVC
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Condensation Polymers: Nylon, Bakelite
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Biodegradable Polymers: PHBV, Polylactic acid
15. Chemistry in Everyday Life
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Drugs: Analgesics, Antipyretics, Antibiotics
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Cleansing Agents: Soaps and Detergents
Conclusion
Revision of short notes and formulas of Class 12 Chemistry (Bihar Board) helps students strengthen their concepts and saves time during exam preparation. These formulas cover important topics of both Physical and Organic Chemistry, making them valuable for last-minute preparation.
FAQs on Bihar Board Class 12th Chemistry Notes
Q1. How can I study Class 12 Chemistry effectively for Bihar Board exams?
Answer: Focus on NCERT textbooks, revise formulas daily, practice numerical problems, and prepare short notes for quick revision before exams.
Q2. Which chapters are most important in Class 12 Chemistry for Bihar Board?
Answer: Solid State, Solutions, Electrochemistry, Chemical Kinetics, p-block elements, d-block elements, and Organic Chemistry chapters are highly important.
Q3. Are these Chemistry formulas useful for competitive exams like JEE and NEET?
Answer: Yes, most of these formulas are directly useful for JEE (Mains + Advanced) and NEET as well.
Q4. What is the best way to memorize Chemistry formulas?
Answer: Revise regularly, write formulas on flashcards, and practice through solved examples to strengthen memory.
Q5. How many marks does Chemistry carry in Bihar Board Class 12 exams?
Answer: Chemistry is of 70 marks theory + 30 marks practical, making a total of 100 marks.
Q6. What are some quick revision tips for Chemistry?
Answer: Revise chapter-wise notes, solve previous year papers, focus on reaction mechanisms in Organic Chemistry, and revise numerical formulas from Physical Chemistry.
Q7. Can short notes help in last-minute preparation?
Answer: Yes, short notes and formula sheets save time during last-minute revision and help recall concepts quickly.
Q8. Is NCERT enough for Bihar Board Chemistry exam?
Answer: Yes, NCERT is the main book for Bihar Board. Along with NCERT, practice previous year question papers for better results.
Q9. Which part of Chemistry is toughest for students?
Answer: Most students find Organic Chemistry reactions and Physical Chemistry numerical challenging, but with practice, they become easier.
Q10. How much time should I give daily to Chemistry revision?
Answer: At least 1–2 hours daily is enough if you revise formulas, reactions, and practice questions consistently.
Q11. How can I score 90+ marks in Class 12 Chemistry (Bihar Board)?
Answer: Study NCERT thoroughly, revise formulas daily, solve numerical problems, and practice previous 10-year question papers.
Q12. Are derivations and reactions important in Class 12 Chemistry exams?
Answer: Yes, reaction mechanisms in Organic Chemistry and derivations in Physical Chemistry are frequently asked in exams.
Q13. Which Chemistry chapters carry more weightage in Bihar Board exams?
Answer: Electrochemistry, Chemical Kinetics, Organic Chemistry, and p-block elements usually carry higher weightage.
Q14. How to prepare Organic Chemistry for Bihar Board Class 12?
Answer: Make a reaction chart, focus on name reactions, practice conversions, and revise reagents with their uses.
Q15. Do practicals play an important role in Class 12 Chemistry?
Answer: Yes, practicals carry 30 marks. Experiments, salt analysis, and viva questions can improve your overall score.