Class 12 Chemistry Complete Notes: All Chapters Formulas, Examples & Questions

Chemistry in Class 12 is divided into three parts: Physical Chemistry, Inorganic Chemistry, and Organic Chemistry.
Success in Board Exams, JEE, and NEET requires a clear understanding of formulas, equations, and their applications.

This blog provides a chapter-wise complete guide with:

• Important formulas

• Solved examples

• Practice questions with answers

Class 12 Chemistry Complete Notes Complete Notes: All Chapters Formulas, Examples & Questions

Chapter 1: Solid State

Important Formulas

• Density:

ρ=Z×Ma3×NA\rho = \frac{Z \times M}{a^3 \times N_A}ρ=a3×NA​Z×M​

• Radius relation:
  SC: r=a2r=\tfrac{a}{2}r=2a​, BCC: r=3a4r=\tfrac{\sqrt{3}a}{4}r=43​a​, FCC: r=2a4r=\tfrac{\sqrt{2}a}{4}r=42​a​

• Packing efficiency: SC=52.4%, BCC=68%, FCC=74%

Example

Q: Find radius in BCC with $a=400$ pm.
A: r=3a4=173.2 pmr = \tfrac{\sqrt{3}a}{4} = 173.2 \, pmr=43​a​=173.2pm

Practice Question

Q1: A metal crystallizes in FCC with edge = 500 pm. M = 60 g/mol. Find density.
Answer: ρ≈2.84 g/cm3\rho \approx 2.84 \, g/cm^3ρ≈2.84g/cm3

Chapter 2: Solutions

Important Formulas

• Molality: m=nsoluteWsolvent(kg)m=\tfrac{n_{solute}}{W_{solvent}(kg)}m=Wsolvent​(kg)nsolute​​

• Osmotic pressure: $\pi =iCRT$

• Elevation of boiling point: ΔTb=iKbm\Delta T_b = iK_bmΔTb​=iKb​m

• Depression of freezing point: ΔTf=iKfm\Delta T_f = iK_fmΔTf​=iKf​m

Example

Q: Osmotic pressure of 0.1 M NaCl at 27°C.
A: $\pi =4.92atm$

Practice Question

Q2: 18 g glucose in 100 g water. Find ΔTf. (Kf=1.86 K kg/mol).
Answer: ΔTf=1.86K\Delta T_f = 1.86 KΔTf​=1.86K

Chapter 3: Electrochemistry

Important Formulas

• Ecell=Ecathode−EanodeE_{cell} = E_{cathode} – E_{anode}Ecell​=Ecathode​−Eanode​

• Nernst: E=E∘−0.059nlog⁡QE = E^\circ – \tfrac{0.059}{n}\log QE=E∘−n0.059​logQ

• ΔG: $\Delta G=-nFE$

• Molar conductivity: Λm=κ×1000C \Lambda_m = \tfrac{\kappa \times 1000}{C}Λm​=Cκ×1000​

Example

Q: ΔG for n=2, E=1.1 V.
A: $-212.3kJ$

Practice Question

Q3: Zn|Zn²⁺ (0.01 M)||Cu²⁺ (1 M)|Cu, find Ecell.
Answer: $E=1.13V$

Chapter 4: Chemical Kinetics

Important Formulas

• Rate law: r=k[A]m[B]n r=k[A]^m[B]^nr=k[A]m[B]n

• First-order: k=2.303tlog⁡[R]0[R]k=\tfrac{2.303}{t}\log\tfrac{[R]_0}{[R]}k=t2.303​log[R][R]0​​

• Half-life (1st order): t1/2=0.693k t_{1/2}=\tfrac{0.693}{k}t1/2​=k0.693​

• Arrhenius: k=Ae−EaRT k=Ae^{-\tfrac{E_a}{RT}}k=Ae−RTEa​​

Example

Q: Half-life = 69.3 s → k=0.01s−1 k=0.01 s^{-1}k=0.01s−1

Practice Question

Q4: 25% decomposes in 20 min. Find t½.
Answer: t1/2=24 mint_{1/2}=24 \, mint1/2​=24min

Chapter 5: Surface Chemistry

Important Formulas

• Freundlich: x/m=kP1/nx/m = kP^{1/n}x/m=kP1/n

• Langmuir: θ=KP1+KP\theta=\tfrac{KP}{1+KP}θ=1+KPKP​

Example

Q: If x/m=5P1/2x/m=5P^{1/2}x/m=5P1/2, at P=16 atm, find x/m.
A: 20

Practice Question

Q5: Distinguish physisorption vs chemisorption.
Answer: Weak van der Waals vs strong chemical bonds.

Chapter 6: General Principles of Metallurgy

Key Formulas/Concepts

• % Metal: %M=Mass of MetalMass of Ore×100\%\text{M}=\tfrac{Mass\,of\,Metal}{Mass\,of\,Ore}\times100%M=MassofOreMassofMetal​×100

• Ellingham: $\Delta G=\Delta H-T\Delta S$

Example

Q: Reaction of Fe₂O₃ with CO.
A: Fe2O3+3CO→2Fe+3CO2Fe_2O_3+3CO \rightarrow 2Fe+3CO_2Fe2​O3​+3CO→2Fe+3CO2​

Practice Question

Q6: Write reaction for Al extraction by Hall-Héroult.
Answer: Al2O3+3C→4Al+3CO2 Al_2O_3+3C \rightarrow 4Al+3CO_2Al2​O3​+3C→4Al+3CO2​

Chapter 7: p-Block Elements

Important Reactions

• 3O2→UV2O33O_2 \xrightarrow{UV} 2O_33O2​UV​2O3​

• 2H2O2→2H2O+O22H_2O_2 \rightarrow 2H_2O+O_22H2​O2​→2H2​O+O2​

• NH3+HCl→NH4ClNH_3+HCl\rightarrow NH_4ClNH3​+HCl→NH4​Cl

Example

Q: Write structure of HNO₃.
A: Planar, N at center with one double bonded O and OH.

Practice Question

Q7: Why does NH₃ act as Lewis base?
Answer: Lone pair on N donates electrons.

Chapter 8: d-Block Elements

Formula

• Magnetic moment: μ=n(n+2)BM \mu=\sqrt{n(n+2)}BMμ=n(n+2)​BM

Example

Q: Magnetic moment of Mn²⁺ (d⁵).
A: 5.92 BM

Practice Question

Q8: Why transition metals show variable oxidation states?
Answer: Due to small energy difference between (n-1)d and ns orbitals.

Chapter 9: f-Block Elements

Key Points

• Lanthanide contraction

• Actinides radioactive

Example

Q: Why actinides show more oxidation states?
A: Small energy difference in 5f, 6d, 7s orbitals.

Practice Question

Q9: Write uses of lanthanides.
Answer: Used in alloys, catalysts, phosphors.

Chapter 10: Coordination Compounds

Important Formulas

• CFT splitting: Δ₀

• Magnetic moment: μ=n(n+2)BM \mu=\sqrt{n(n+2)}BMμ=n(n+2)​BM

Example

Q: Name [Co(NH₃)₆]Cl₃.
A: Hexaamminecobalt(III) chloride

Practice Question

Q10: Write IUPAC name of [Fe(CN)₆]⁴⁻.
Answer: Hexacyanoferrate(II)

Chapter 11: Haloalkanes & Haloarenes

Reactions

• Substitution: R−X+OH−→R−OH+X−R-X+OH^- \rightarrow R-OH+X^-R−X+OH−→R−OH+X−

• Elimination: R−CH2CH2X→alc.KOHR−CH=CH2R-CH_2CH_2X \xrightarrow{alc.KOH} R-CH=CH_2R−CH2​CH2​Xalc.KOH​R−CH=CH2​

Example

Q: Convert chloroethane to ethanol.
A: C₂H₅Cl + NaOH → C₂H₅OH

Practice Question

Q11: Write reaction of chlorobenzene with NaOH (at 623K, 300 atm).
Answer: Produces phenol.

Chapter 12: Alcohols, Phenols & Ethers

Reactions

• Oxidation: R−CH2OH→KMnO4R−COOHR-CH_2OH \xrightarrow{KMnO_4} R-COOHR−CH2​OHKMnO4​​R−COOH

• Williamson: R−X+R’O−→R−O−R’R-X+R’O^- \rightarrow R-O-R’R−X+R’O−→R−O−R’

Example

Q: Prepare anisole from phenol.
A: Phenol + NaOH → Sodium phenoxide → + CH₃I → Anisole

Practice Question

Q12: Distinguish phenol from alcohol.
Answer: Phenol gives violet color with FeCl₃, alcohol does not.

Chapter 13: Aldehydes, Ketones & Carboxylic Acids

Reactions

• Aldol: 2CH3CHO→NaOHCH3CH(OH)CH2CHO2CH_3CHO \xrightarrow{NaOH} CH_3CH(OH)CH_2CHO2CH3​CHONaOH​CH3​CH(OH)CH2​CHO

• Cannizzaro: 2HCHO+NaOH→HCOONa+CH3OH2HCHO+NaOH \rightarrow HCOONa+CH_3OH2HCHO+NaOH→HCOONa+CH3​OH

Example

Q: Test for aldehyde group.
A: Tollens’ reagent test → silver mirror.

Practice Question

Q13: Write product of CH₃CHO + HCN.
Answer: CH₃CH(OH)CN

Chapter 14: Amines

Reactions

• Hoffmann: RCONH2+Br2+4NaOH→RNH2+Na2CO3+2NaBr+2H2ORCONH_2+Br_2+4NaOH \rightarrow RNH_2+Na_2CO_3+2NaBr+2H_2ORCONH2​+Br2​+4NaOH→RNH2​+Na2​CO3​+2NaBr+2H2​O

• Diazotisation: ArNH2+NaNO2+HCl→ArN2+Cl−+2H2OArNH_2+NaNO_2+HCl \rightarrow ArN_2^+Cl^-+2H_2OArNH2​+NaNO2​+HCl→ArN2+​Cl−+2H2​O

Example

Q: Write diazotisation of aniline.
A: C₆H₅NH₂ + NaNO₂ + HCl → C₆H₅N₂⁺Cl⁻

Practice Question

Q14: Distinguish primary, secondary, tertiary amines by Hinsberg test.
Answer: Primary soluble, secondary insoluble solid, tertiary no reaction.

Chapter 15: Biomolecules

Key Points

• Glucose: C₆H₁₂O₆

• DNA = double helix

• Amino acids: H₂N-CHR-COOH

Example

Q: Write structure of α-glucose.
A: Six-membered ring with OH below C1.

Practice Question

Q15: Which bond links amino acids in proteins?
Answer: Peptide bond.

Chapter 16: Polymers & Chemistry in Everyday Life

Examples

• Addition: Polyethylene

• Condensation: Nylon-6,6

• Drugs: Analgesics, Antibiotics

Example

Q: Write reaction for nylon-6,6 formation.
A: Hexamethylene diamine + adipic acid → Nylon-6,6

Practice Question

Q16: Which polymer is used in bullet-proof jackets?
Answer: Kevlar

Conclusion

This blog provides a complete chapter-wise guide for Class 12 Chemistry( Class 12 Chemistry Complete Notes Complete Notes) including all important formulas, solved examples, and practice questions with answers.

It is a perfect revision resource for Boards, JEE, and NEET.

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Class 12 Chemistry Complete Notes Complete Notes

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