Class XII Chemistry - neetpath.in

NEET 2025 • Class XII Chemistry

NCERT 2025–26: Class 12 Chemistry Hub — Notes, Figures, Summaries, Quizzes & Downloads

This hub brings together all ten NCERT units/chapters — Solutions, Electrochemistry, Chemical Kinetics, d- & f-Block Elements, Coordination Compounds, Haloalkanes & Haloarenes, Alcohols–Phenols–Ethers, Aldehydes–Ketones–Carboxylic Acids, Amines, and Biomolecules — with chapters 1–10 presented in a consistent, exam-ready format. Every chapter block follows the same layout: Notes → Figures → Quick Summary → 10-MCQ Quiz → Downloads. Use the sticky contents at left to jump between chapters, and the search box to filter chapters live on this page.

Syllabus verified • Updated: 06 Sep 2025

Unit Overview

This page is your master table of contents for NCERT Class XII Chemistry. Chapters are ordered as in the official syllabus, and each chapter block is self-contained for teaching and revision: topic-wise notes with definitions & logic, diagram/mechanism callouts, a quick summary for last-minute revision, a 10-MCQ quiz for NEET/Boards pattern practice, and downloads (formula sheets, reaction maps, tables). Progress chips flag weightage (High/Medium), numerical/derivation density, and PYQ focus to help you prioritise.

High-yield PYQs Mechanism maps Numerical practice Quick revision sheets

01 Solutions

Summative Weightage: High Updated: 09 Sep 2025

Chapter Notes

Solutions are homogeneous mixtures; the solvent defines the physical state.
Types by state: gaseous (e.g., O₂ in N₂), liquid (e.g., ethanol in water), solid (e.g., H₂ in Pd; alloys).
Concentration units: mass% (w/w), volume% (v/v), w/V, ppm, mole fraction (x), molarity (M), molality (m).
M is temperature-dependent (volume varies); m, x, mass% and ppm are temperature-independent.
Solubility: “like dissolves like”; solids in liquids—T effect depends on ΔH_sol; pressure has negligible effect.
Gases in liquids: solubility ↑ with pressure (Henry’s law p = K_Hx), ↓ with temperature (exothermic dissolution).
Vapour pressure: non-volatile solute lowers p_solvent; for volatile–volatile mixtures, Raoult’s law applies.
Ideal vs non-ideal: ideal obey Raoult’s law across range (ΔH_mix=0, ΔV_mix=0); non-ideal show ± deviations and may form azeotropes.
Colligative properties depend on particle number: RLVP, ΔT_b = K_bm, ΔT_f = K_fm, Π = CRT.
Van’t Hoff factor (i) adjusts for association/dissociation: use iK, iC in colligative relations.
Applications: soft drinks (CO₂ pressure), scuba diving (He–N₂–O₂ mix), RO desalination (pressure > Π).

Important Figures

Matrix of solution types by solute and solvent states — Solution types across gas/liquid/solid with examples.

Raoult’s law with positive and negative deviations and azeotrope points — Raoult’s law: ideal vs deviations; min/max boiling azeotropes.

Colligative properties overview — RLVP, ΔT_b, ΔT_f, Π—definitions and relations.

Quick Summary

Focus on when to use M vs m, Henry’s and Raoult’s laws, recognizing deviations (positive/negative) and azeotropes, and inserting van’t Hoff factor i for associating/dissociating solutes in colligative-property numericals.

Practice Quiz (10 MCQs)

1) Which concentration unit is temperature-dependent?

2) Henry’s law for gas solubility at constant temperature is:

3) For an ideal binary solution obeying Raoult’s law:

4) Ethanol + acetone shows positive deviation. Correct inference:

5) For a non-volatile solute in a volatile solvent (dilute), RLVP equals:

6) Best method to determine molar mass of a heat-sensitive polymer in water:

7) Van’t Hoff factor (i) statement that is correct:

8) Elevation of boiling point for dilute solutions is:

9) Gas solubility in a liquid generally:

10) An azeotrope is a mixture that:

Downloads

Formula Sheet (PDF) Colligative Properties – Practice Set (PDF)

02 Electrochemistry

Summative Weightage: High Updated: 09 Sep 2025

Chapter Notes

Electrochemistry studies conversion between chemical and electrical energy: spontaneous reactions (galvanic cells) produce electricity; non-spontaneous reactions (electrolytic cells) are driven by electricity.
Galvanic cell example (Daniell): Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s); anode (oxidation) is negative, cathode (reduction) is positive; electrons flow anode → cathode.
Electrode potential arises at metal–solution interface; standard electrode potentials are IUPAC standard reduction potentials.
Standard Hydrogen Electrode (SHE): Pt(s)|H₂(g, 1 bar)|H⁺(aq, 1 M); assigned 0.00 V by convention and used to measure E° of other half-cells.
Cell potential (emf) under no current: E_cell = E_right − E_left; for standard state E°_cell = E°_cathode − E°_anode.
Nernst: E_cell = E°_cell − (RT/nF) ln Q; at 298 K, E_cell = E°_cell − (0.059/n) log Q.
Thermo links: Δ_rG = −nFE_cell; Δ_rG° = −nFE°_cell; E°_cell = (2.303RT/nF) log K and Δ_rG° = −RT ln K.
Conductivity κ decreases with dilution; molar conductivity Λ_m = κ/c increases with dilution. Limiting molar conductivity Λ°_m at infinite dilution.
Kohlrausch’s law: Λ°_m = ν⁺λ°⁺ + ν⁻λ°⁻ (sum of ionic contributions), useful for weak electrolytes and dissociation constants.
Electrolysis: Faraday’s laws; Q = It; products depend on E° values, electrode type, and overpotential.
Batteries: primary (dry cell ~1.5 V, mercury ~1.35 V), secondary (lead–acid, Ni–Cd); Fuel cells (H₂–O₂) produce water with high efficiency.
Corrosion (e.g., rusting of iron) is electrochemical; prevent via coatings or sacrificial anodes (Zn, Mg).
Hydrogen economy: use renewable H₂ (electrolysis) and fuel cells for clean energy.

Important Figures

Schematic of Daniell galvanic cell with electron flow and salt bridge — Daniell cell: electron flow anode → cathode; salt bridge completes the circuit.

Nernst equation effect of concentration on cell potential — Nernst relation: E vs log Q at 298 K with slope −0.059/n.

Variation of conductivity and molar conductivity with dilution — κ decreases with dilution; Λ_m increases; Λ°_m by extrapolation for strong electrolytes.

Quick Summary

Know cell conventions (anode/cathode signs, electron flow), write Nernst quickly at 298 K, connect E° to ΔG° and K, and distinguish κ vs Λ_m. For numericals, identify n, pick correct Q, and keep units consistent with F ≈ 96,487 C mol⁻¹.

Practice Quiz (10 MCQs)

1) In a galvanic (voltaic) cell:

2) The approximate standard emf of the Daniell cell Zn|Zn²⁺(1 M)||Cu²⁺(1 M)|Cu is:

3) By convention, the Standard Hydrogen Electrode (SHE) potential is:

4) The Nernst equation for cell potential at 298 K is:

5) The correct thermodynamic relation is:

6) The relation between standard emf and equilibrium constant at 298 K is:

7) With dilution of an electrolyte solution:

8) Kohlrausch’s law of independent migration of ions states that:

9) During electrolysis, the mass of substance liberated is proportional to:

10) In the hydrogen–oxygen fuel cell operating in alkaline medium, the main product at the overall reaction is:

Downloads

Electrochemistry Formula Sheet (PDF) Practice Numericals – Nernst & Faraday (PDF)

03 d- and f-Block Elements

Summative Weightage: High Updated: 09 Sep 2025

Chapter Notes

d-block (groups 3–12) and f-block (4f/5f) metals have partially filled d or f orbitals; they underpin metallurgy, catalysis, batteries, and nuclear energy.
IUPAC: transition metals have an incomplete d subshell in the atom or in common ions; Zn, Cd, Hg are not strictly transition (d¹⁰), though studied alongside.
Electronic configuration: general (n−1)d^1–10 ns^1–2 with exceptions (Cr: 3d⁵4s¹, Cu: 3d¹⁰4s¹) due to extra stability of half/full d.
Physical properties: high strength, hardness, m.p./b.p., metallic lustre, good thermal/electrical conductivity; high enthalpy of atomization.
Sizes: across a series radii decrease; lanthanoid contraction makes many 4d/5d pairs (e.g., Zr–Hf) nearly identical in size and properties.
Ionisation enthalpies increase across a series; ns electrons are lost before (n−1)d on ion formation; stability of d⁵, d¹⁰ causes irregularities.
Oxidation states: multiple states (often differ by 1); mid-series elements show the widest range (Mn: +2 to +7). Higher states stabilize down a group (e.g., Mo(VI), W(VI)).
Redox/E° trends: E°(M²⁺/M) becomes less negative across; Cu has +0.34 V (does not liberate H₂ from acids) due to atomization/hydration energetics.
Magnetism: many ions are paramagnetic; spin-only μ = √(n(n+2)) BM (n = unpaired electrons).
Colour: d–d transitions in partially filled d subshells cause coloured ions/solids.
Complex formation: favored by small, highly charged cations with accessible d orbitals; rich coordination chemistry.
Catalysis: variable oxidation states and surface adsorption enable catalysis (V₂O₅, Fe/Haber, Ni/hydrogenation, PdCl₂/Wacker).
Interstitial compounds and alloys: small atoms (H, C, N) occupy interstices; similar radii promote alloying.
Key compounds: K₂Cr₂O₇ (strong oxidant in acid; chromate–dichromate pH interconversion), KMnO₄ (prepared via alkaline manganate and electrolytic oxidation; potent oxidant in acid/neutral/alkaline media).
f-block: lanthanoids (Ce–Lu) mainly +3 (also +2/+4 for f⁰, f⁷, f¹⁴ cases); actinoids (Th–Lr) show wider oxidation states (+3 to +7) and stronger 5f participation; both show contraction.
Applications: steels, catalysts, pigments (TiO₂), batteries (MnO₂, Zn, Ni/Cd), coinage alloys (Ag, Au, Cu/Ni), photography (AgBr), nuclear energy (Th, Pa, U).

Important Figures

3d, 4d, 5d series layout with common oxidation states — 3d/4d/5d series with common oxidation states across groups.

Plot illustrating lanthanoid contraction and Zr–Hf size similarity — Lanthanoid contraction: near-equality of 4d/5d radii (e.g., Zr≈Hf).

Chromate–dichromate pH interconversion and KMnO4 preparation — CrO₄²⁻ ⇌ Cr₂O₇²⁻ with pH; overview of KMnO₄ manufacture.

Quick Summary

Remember the IUPAC definition, Cr/Cu exceptions, the effect of lanthanoid contraction, oxidation-state patterns (Mn widest in 3d), spin-only magnetism, and the oxidative roles of dichromate and permanganate. For f-block, default +3 for lanthanoids with notable +2/+4 cases, and broader oxidation range for actinoids.

Practice Quiz (10 MCQs)

1) According to IUPAC, a transition metal is one that:

2) Which set is not strictly considered transition metals by IUPAC, yet often studied with them?

3) The anomalous ground-state configurations due to extra stability of half/full d subshells occur in:

4) A key consequence of lanthanoid contraction is that:

5) Which 3d element exhibits the widest range of oxidation states (+2 to +7)?

6) The spin-only magnetic moment for high-spin Mn²⁺ (d⁵) is closest to:

7) The colour of many transition-metal ions in solids/solutions mainly arises from:

8) Potassium dichromate, K₂Cr₂O₇, acts as a strong oxidising agent chiefly in:

9) Which statement about KMnO₄ is correct?

10) The predominant oxidation state of lanthanoids and the reason additional +2/+4 states appear is:

Downloads

d-/f-Block Formula & Trends (PDF) Chromate–Dichromate & Permanganate Reactions (PDF)

04 d- and f-Block Elements

Summative Weightage: High Updated: 09 Sep 2025

Chapter Notes

Location & definition: d-block (Groups 3–12) fills (n−1)d orbitals; f-block (4f/5f) sits separately below the table.
IUPAC transition metal: metal with an incomplete d subshell in atom or in its common ions. Group 12 (Zn, Cd, Hg, Cn) are not strictly transition (d¹⁰), though studied together.
Electronic configuration: general (n−1)d^1–10 ns^1–2; stability of half/full d gives exceptions (Cr: 3d⁵4s¹, Cu: 3d¹⁰4s¹; Pd: 4d¹⁰5s⁰).
Physical properties: high strength, hardness, m.p./b.p., metallic lustre; high enthalpy of atomisation (peaks around d⁵); density rises Ti→Cu.
Sizes: radii decrease across a series; lanthanoid contraction makes many 4d/5d pairs (e.g., Zr–Hf) nearly identical in size/properties.
Ionisation enthalpies: increase across a series; ns lost before (n−1)d on ionisation; irregularities due to d⁰, d⁵, d¹⁰ stabilities.
Oxidation states: multiple and often differ by 1; widest near mid-series (Mn: +2 to +7). Higher states stabilised by O/F; π-acceptor ligands stabilise low/zero states (e.g., Ni(CO)₄).
Standard potentials: E°(M²⁺/M) trend becomes less negative across; Cu has +0.34 V (does not liberate H₂ from acids). Mn³⁺, Co³⁺ strong oxidants; Ti²⁺, V²⁺, Cr²⁺ strong reductants.
Magnetism: many ions are paramagnetic; spin-only μ = √(n(n+2)) BM (n = unpaired electrons); some show ferro/antiferromagnetism.
Colour: arises mainly from d–d transitions in partially filled d subshells.
Complex formation: small, highly charged cations with accessible d orbitals form numerous complexes.
Catalysis: variable oxidation states and adsorption enable catalysis (V₂O₅, Fe/Haber, Ni/H₂, PdCl₂/Wacker).
Interstitial compounds & alloys: H/C/N in interstices → very hard, high m.p., metallic conductivity; similar radii promote alloying (steels, brass, bronze).
Key compounds: K₂Cr₂O₇ (acidic medium oxidant; chromate⇌dichromate with pH), KMnO₄ (from alkaline manganate via electrolysis; strong oxidant—products depend on pH).
f-block overview: lanthanoids (Ce–Lu) mainly +3, some +2/+4 due to f⁰, f⁷, f¹⁴ stability; actinoids (Th–Lr) wider range (+3 to +7), stronger 5f participation; both show contraction (actinoid > lanthanoid).
Applications: steels (Fe/Cr/Mn/Ni), pigments (TiO₂), batteries (MnO₂, Zn, Ni/Cd), coinage (Ag, Au, Cu/Ni), photography (AgBr), nuclear energy (Th, Pa, U).

Important Figures

d-block series map (3d/4d/5d) with typical oxidation states — 3d/4d/5d layout with common oxidation state patterns.

Plot of ionic radii showing lanthanoid contraction and Zr–Hf similarity — Lanthanoid contraction: near-equal radii for Zr–Hf (4d/5d).

Chromate–dichromate interconversion and KMnO4 redox in different pH — CrO₄²⁻ ⇌ Cr₂O₇²⁻ (pH); KMnO₄ reduction products vs pH.

Quick Summary

Anchor on the IUPAC definition, Cr/Cu/Pd exceptions, lanthanoid contraction (Zr≈Hf), oxidation-state breadth (Mn widest), roles of O/F in stabilising high states, and why Cu (E° = +0.34 V) won’t liberate H₂. Know dichromate/permanganate prep and redox across media, and the lanthanoid (+3) vs actinoid (broader) contrast.

Practice Quiz (10 MCQs)

1) By IUPAC, a transition metal is one that:

2) Which set is not strictly considered transition metals?

3) Which configurations reflect the well-known exceptions due to half/full d stability?

4) A key consequence of the lanthanoid contraction is:

5) Which 3d element exhibits the widest range of oxidation states (+2 to +7)?

6) Which statement best explains why Cu does not liberate H₂ from dilute acids?

7) The principal origin of colour in many transition-metal compounds is:

8) K₂Cr₂O₇ behaves as a strong oxidising agent chiefly in:

9) In acidic solution, the reduction product of permanganate ion is:

10) Interstitial compounds of transition metals typically:

Downloads

d/f-Block Formulae & Trends (PDF) Dichromate & Permanganate Reactions (PDF)

05 Coordination Compounds

Summative Weightage: High Updated: 09 Sep 2025

Chapter Notes

Coordination compounds: metal center bound to anions/neutral molecules via donor atoms; key to bioinorganic systems (chlorophyll, haemoglobin, B₁₂), catalysis, analysis, metallurgy, electroplating, dyes, and medicine.
Werner’s theory (1898): metals exhibit primary valence (oxidation state; ionisable) and secondary valence (coordination number; non-ionisable, fixed geometry). Species inside [ ] act as one undissociated entity.
Key terms: coordination entity [ ], central ion (Lewis acid), ligands (uni/di/poly-dentate; chelating; ambidentate such as NO₂⁻/ONO⁻, SCN⁻/NCS⁻), coordination number (donor atoms bound), coordination sphere, polyhedra (octahedral, square planar, tetrahedral), oxidation number, homoleptic vs heteroleptic.
IUPAC naming: list ligands (alphabetical; anionic “-o/-ido”, neutral special names ammine/aqua/carbonyl/nitrosyl), prefixes (di/tri…; bis/tris for complex ligand names), metal with oxidation state in Roman numerals; “-ate” for anionic complexes.
Isomerism: Stereoisomerism—geometrical (cis–trans; fac–mer) and optical (enantiomers; common with didentate ligands e.g., [Co(en)₃]³⁺). Structural—linkage (NO₂ vs ONO), coordination, ionisation, and solvate (hydrate) isomerism.
VBT: hybridisation model (sp³, dsp², d²sp³/sp³d²) explains geometry and (dia/para)magnetism via paired/unpaired d electrons; limited for colours and thermodynamics.
CFT: electrostatic model; d-orbital splitting—octahedral Δ_o (e_g higher, t_2g lower), tetrahedral Δ_t = 4/9 Δ_o (inverted order). Spectrochemical series: I⁻ < Br⁻ < Cl⁻ < F⁻ < H₂O < NH₃ < en < NO₂⁻ < CN⁻ < CO. Colour from d–d transitions; magnetic behaviour from unpaired count (Δ vs pairing energy P).
Metal carbonyls: synergic bonding—σ donation (CO → M) + π back-donation (M d → CO π*), strengthening M–CO.
Applications: EDTA complexometry (hardness), cyanidation/extraction and Mond process [Ni(CO)₄], catalysis (Wilkinson’s catalyst, V₂O₅, Fe/Haber), electroplating via complexes ([Ag(CN)₂]⁻), photography (AgBr + thiosulfate), chelation therapy (EDTA, D-penicillamine, desferrioxamine), antitumor agents (cis-platin).

Important Figures

Common coordination polyhedra: octahedral, square planar, tetrahedral — Coordination polyhedra and typical CN values.

CFT splitting diagrams for octahedral and tetrahedral fields — Octahedral (Δ_o) vs tetrahedral (Δ_t=4/9 Δ_o) splitting.

fac–mer and cis–trans isomerism examples with didentate ligands — Geometrical & optical isomerism in [Ma₃b₃] and chelates.

Quick Summary

Map Werner’s primary vs secondary valences, practice IUPAC names, and classify isomerism (linkage/ionisation/coordination vs cis–trans/fac–mer and optical). For bonding, contrast VBT (hybrid + spin) with CFT (Δ, spectrochemical series, colour, magnetism). Remember synergic M–CO bonding and core applications (EDTA, cyanidation, plating, cis-platin).

Practice Quiz (10 MCQs)

1) In Werner’s theory, the secondary valence corresponds to:

2) In [Co(NH₃)₅Cl]Cl₂, the coordination number and oxidation state of Co are:

3) Which pair represents linkage isomers?

4) For an octahedral [Ma₃b₃] complex, the number of geometrical isomers is:

5) Which complex shows optical isomerism most readily?

6) A correct segment of the spectrochemical series (increasing field strength) is:

7) An octahedral d⁶ complex with strong-field ligands (e.g., CN⁻) is expected to be:

8) Which statement about CFT splitting is correct?

9) Metal–CO bonding in carbonyls is best described as:

10) EDTA in water-hardness determination acts as:

Downloads

IUPAC Nomenclature & Isomerism (PDF) CFT & Spectrochemical Series Sheet (PDF)

06 Haloalkanes & Haloarenes

Summative Weightage: High Updated: 09 Sep 2025

Chapter Notes

Definitions: Haloalkanes (alkyl halides): X on sp³ C of an alkyl group. Haloarenes (aryl halides): X directly on sp² C of an aromatic ring.
Classification: 1°, 2°, 3° (by carbon type); mono/di/poly-halo; allylic/benzylic (sp³–X adjacent to C=C or aryl), vinylic/aryl (sp²–X). Dihaloalkanes: geminal vs vicinal.
Nomenclature: IUPAC halosubstituted names (e.g., 2-chlorobutane); o/m/p (common) vs 1,2/1,3/1,4 (IUPAC) for dihalobenzenes.
C–X bond: Polar (δ⁺ on C, δ⁻ on X). Bond length ↑ and bond enthalpy ↓ from C–F → C–I.
Preparation (haloalkanes): ROH → RX (HX, PCl_3/5, SOCl₂—preferred; gaseous by-products). Alkenes + HX (Markovnikov), +X₂ (vic-dihalides), free-radical halogenation (mixtures). Halogen exchange: Finkelstein (NaI/acetone → RI), Swarts (AgF/CoF₂ → RF).
Preparation (haloarenes): Electrophilic substitution (Cl₂/Br₂ + Lewis acid); Sandmeyer (ArN₂⁺ → ArCl/ArBr; KI for ArI).
Physical properties: b.p. RI > RBr > RCl > RF (for same R); branching lowers b.p.; p-dihalobenzenes have higher m.p. (better packing). Slightly water-soluble; denser with heavier X/more X.
Reactivity (haloalkanes): Nucleophilic substitution (S_N2: backside attack, inversion; rate ~ [RX][Nu⁻], Me > 1° > 2° > 3°. S_N1: carbocation, racemisation; rate ~ [RX], 3° > 2° > 1° > Me). Leaving group: I⁻ > Br⁻ > Cl⁻ ≫ F⁻. Ambident nucleophiles: KCN → R–C≡N; AgCN → R–N≡C.
Elimination (β, E2): alc. KOH gives alkenes; Zaitsev’s rule → more substituted alkene major. Competition: S vs E depends on substrate/base/solvent/T.
Metals: Grignard RMgX (dry ether); Wurtz (R–X + 2Na → R–R); Wurtz–Fittig/Fittig for aryl systems.
Haloarenes: Nucleophilic substitution is difficult (resonance → partial double bond; sp²–X shorter/stronger; unstable phenyl cation; π–π repulsion). –NO₂ at o/p activates towards S_NAr; meta has little effect. Electrophilic substitution: X is deactivating (−I) but o/p-directing (resonance).
Polyhalogen compounds & environment: CHCl₃ → phosgene in air/light (store dark); CCl₄, CFCs deplete ozone; DDT bioaccumulates; many are toxic (CNS, liver/kidney).

Important Figures

Classification tree of haloalkanes and haloarenes with allylic, benzylic, vinylic, aryl — Classification: sp³–X (allylic/benzylic) vs sp²–X (vinylic/aryl).

Comparative energy diagrams for SN1 and SN2 mechanisms — S_N2 single-step inversion vs S_N1 two-step via carbocation (racemisation).

Effect of nitro groups at ortho/para positions on nucleophilic substitution in haloarenes — o/p-NO₂ stabilises Meisenheimer intermediate → faster S_NAr.

Quick Summary

Know classes (allylic/benzylic/vinylic/aryl), C–X trends (C–F strongest), key preparations (SOCl₂, Finkelstein/Swarts, Sandmeyer), and outcomes: S_N2 → inversion; S_N1 → racemisation; alc. KOH → Zaitsev alkene. Haloarenes resist S_N but o/p-NO₂ activates. Review environmental hazards of polyhalogen compounds.

Practice Quiz (10 MCQs)

1) A haloarene is a compound in which the halogen is bonded to:

2) Which C–X bond is strongest (highest bond enthalpy)?

3) Which condition most favours an S_N1 pathway?

4) S_N2 on a chiral centre typically gives:

5) β-Elimination of HX with alcoholic KOH generally follows:

6) Best reagent to convert R–OH to R–Cl with clean by-products is:

7) The Finkelstein reaction for preparing R–I uses:

8) Correct reactivity order for S_N2:

9) Haloarenes become more reactive towards nucleophilic substitution when:

10) Which statement is correct about polyhalogen compounds?

Downloads

SN1/SN2 & E2 Quick Sheet (PDF) Environmental Chemistry: Polyhalogen Compounds (PDF)

07 Alcohols, Phenols & Ethers

Summative Weightage: High Updated: 09 Sep 2025

Chapter Notes

Definitions: Alcohols: R–OH on sp³ C (aliphatic); Phenols: Ar–OH on sp² aromatic C; Ethers: R–O–R′/Ar–O–R′.
Classification: mono/di/tri/polyhydric; monohydric by site—1°, 2°, 3°, allylic (next to C=C), benzylic (next to aryl), vinylic (on C=C, sp²). Ethers: simple (sym) vs mixed.
Nomenclature: Alcohols: “alkan-ol” (ethan-1-ol); polyols keep ‘e’ (ethane-1,2-diol). Phenols: o/m/p (common) or 1,2/1,3/1,4 (IUPAC). Ethers: alkoxy-parent (methoxybenzene) or common “alkyl alkyl ether”.
Structure: Alcohol/ether O is sp³; phenolic C–O shorter via resonance (partial double bond). Ether C–O–C angle slightly widened (lone pair–bond pair repulsions + bulky groups).
Preparation (alcohols): alkenes → R–OH by acid hydration (Markovnikov) or hydroboration–oxidation (anti-Markovnikov); carbonyl reductions (NaBH₄/LiAlH₄); acids/esters → 1° ROH (LiAlH₄); Grignard + carbonyls.
Preparation (phenols): from ArX (NaOH, high T/P), from benzenesulphonate (molten NaOH → acidify), from diazonium (hydrolysis), industrial cumene process.
Preparation (ethers): Williamson (R–X + R′O⁻, best with 1° R–X; S_N2); dehydration of 1° alcohols at controlled T (otherwise alkenes form).
Physical trends: Alcohols/phenols H-bond → higher b.p. than isomass ethers/haloalkanes; branching lowers b.p. Solubility in water decreases with longer/larger hydrophobes; small ethers dissolve via H-bond acceptance.
Alcohol reactions: acidity (RO⁻ + H₂), esterification, R–OH → R–X (HX/PX₃/SOCl₂), dehydration (3° > 2° > 1°), oxidation (1° → RCHO/RCOOH; 2° → RCOR′; 3° resist).
Phenol reactions: stronger acid than alcohols/water (phenoxide resonance); EAS o/p-directing (nitration, halogenation), Kolbe (→ salicylic acid), Reimer–Tiemann (→ salicylaldehyde), Zn dust → benzene, oxidation → quinone.
Ether reactions: strong HX cleavage (HI > HBr ≫ HCl); Ar–O–R cleaves at alkyl–O to give Ar–OH + R–X; anisole activates ring o/p (EAS, FC alkyl/acylation, nitration).
Key alcohols: Methanol (CO + H₂ hydrogenation); Ethanol (fermentation; denatured with additives).

Important Figures

Classification of alcohols (1°,2°,3°, allylic, benzylic, vinylic), phenols and ethers — Classification map for ROH/ArOH and R–O–R′.

Markovnikov hydration vs anti-Markovnikov hydroboration–oxidation — Alkene to alcohol: acid hydration vs hydroboration–oxidation.

Kolbe carboxylation, Reimer–Tiemann formylation, anisole cleavage with HI — Signature phenol reactions and ether HI cleavage.

Quick Summary

Choose hydration (Markovnikov) or hydroboration–oxidation (anti-Markovnikov). Use Williamson (S_N2) with 1° halides for ethers. Remember: phenol acidity > water > ethanol; phenoxide is resonance-stabilised. Lucas test: 3° reacts fastest. Phenol gives Kolbe (–COOH ortho) and Reimer–Tiemann (–CHO ortho); anisole cleaves with HI to phenol + R–I.

Practice Quiz (10 MCQs)

1) Which is a benzylic alcohol?

2) Reagents that give an anti-Markovnikov alcohol from an alkene:

3) Best Williamson route to anisole (methoxybenzene):

4) Lucas test shows immediate turbidity at room temperature for:

5) Correct acidity order:

6) Kolbe’s reaction (from phenoxide + CO₂ then acidify) gives mainly:

7) Reimer–Tiemann reaction converts phenol to predominantly:

8) Cleavage of anisole (Ph–O–CH₃) with excess HI at reflux yields:

9) Major product on dehydrating 2-butanol with conc. H₂SO₄ at 443 K:

10) Highest boiling point among the following:

Downloads

Preparation & Reactions Quick Sheet (PDF) Phenol Special Reactions (Kolbe/RT) (PDF)

08 Aldehydes, Ketones & Carboxylic Acids

Summative Weightage: High Updated: 09 Sep 2025

Chapter Notes

Carbonyl family: Aldehydes (R–CHO), ketones (R–CO–R′), and carboxylic acids (R–COOH) revolve around the polar >C=O group (sp², trigonal planar ~120°).
Polarity & reactivity: Cδ⁺ is electrophilic (site for nucleophilic addition). Aldehydes are generally more reactive than ketones (less steric/electronic crowding).
Nomenclature (IUPAC): aldehydes → -al (ring: -carbaldehyde), ketones → -one, carboxylic acids → -oic acid.
Preparations: controlled oxidation/dehydrogenation of alcohols; ozonolysis of alkenes; alkyne hydration (ethyne → ethanal; others → ketones). Special: Rosenmund (acyl chloride → aldehyde), Stephen (RCN → RCHO), DIBAL-H (esters/RCN → aldehydes), Friedel–Crafts acylation (aryl ketones), Grignard + CO₂ (acids).
Physical trends: b.p.: aldehydes/ketones > hydrocarbons (dipoles) but < alcohols (no intermolecular H-bonding). Carboxylic acids dimerise via H-bonds → very high b.p. Lower members are water-miscible.
Nucleophilic additions: HCN (cyanohydrins), NaHSO₃ adducts, alcohols (hemiacetal/acetal; ketal), NH₂Z (imines/oximes/hydrazones).
Redox: Aldehydes → acids (Tollens mirror/Fehling); carbonyl → alcohols (NaBH₄, LiAlH₄). >C=O → >CH₂: Clemmensen (Zn(Hg)/HCl, acidic) or Wolff–Kishner (N₂H₄/KOH, heat, basic).
α-Chemistry: Aldol (needs α-H; gives β-hydroxy carbonyl then dehydration); haloform test for methyl ketones; Cannizzaro (no α-H) disproportionation.
Acid reactions: R–COOH stronger than ROH/ArOH (resonance-stabilised carboxylate); effervescence with NaHCO₃; HVZ α-halogenation (X₂/P).
Uses: formalin (preservative), acetone/MEK (solvents), benzoates/esters (flavours, preservatives), acetic acid (vinegar), higher acids (soaps).

Important Figures

Planar geometry of carbonyl group and polarization of C=O — Carbonyl geometry and C=O polarity (Cδ+ / Oδ−).

Contrasting aldol condensation (with α-H) vs Cannizzaro (no α-H) — Aldol (needs α-H) vs Cannizzaro (no α-H).

Clemmensen vs Wolff–Kishner reductions; HVZ α-halogenation of acids — Clemmensen (acid) / Wolff–Kishner (base) / HVZ (α-halogenation).

Quick Summary

Prioritise nucleophilic addition logic (aldehyde > ketone), match named reactions (Rosenmund, Stephen, DIBAL-H, Gattermann–Koch), and recognise diagnostic tests (Tollens/Fehling, haloform). For acids, remember resonance-stabilised carboxylate, NaHCO₃ effervescence, and HVZ at the α-position.

Practice Quiz (10 MCQs)

1) The IUPAC name of CH₃CHO is:

2) Which reagent set converts an acyl chloride (RCOCl) selectively to an aldehyde (RCHO)?

3) Which gives a silver mirror with Tollens’ reagent?

4) Which compound will undergo Cannizzaro reaction in conc. base?

5) The reaction introducing a formyl (–CHO) group into benzene using CO/HCl, AlCl₃/CuCl is:

6) Regarding nucleophilic addition to carbonyls, which is correct?

7) Which self-condenses in aldol condensation under dilute base?

8) Propanoic acid treated with Br₂/P (red P) chiefly gives:

9) Which compound will give the iodoform test?

10) Which statement about boiling points is correct?

Downloads

Named Reactions & Tests (PDF) Aldol/Cannizzaro/HVZ Cheat Sheet (PDF)

09 Amines & Diazonium Salts

Summative Weightage: High Updated: 09 Sep 2025

Chapter Notes

Structure & classification: Amines are NH₃ derivatives; N is sp³, trigonal pyramidal. Types—1° (RNH₂/ArNH₂), 2° (R₂NH), 3° (R₃N); simple vs mixed.
Nomenclature: Common: alkylamine/arylamine; IUPAC: alkanamine; N-substituents labeled with “N-”. Aniline = benzenamine.
Preparations: Nitro reduction (H₂/Ni, Fe/HCl); ammonolysis of RX (mixtures); RCN/amide reductions (LiAlH₄, H₂); Gabriel (1° only, not aryl); Hofmann bromamide (RCONH₂ → RNH₂ with −1 C).
Physical trends: Lower aliphatic amines—gases (fishy); H-bonding: 1° > 2° > 3° → b.p. order. Water solubility drops with chain length; aniline darkens on storage.
Basicity: Lone pair on N → Lewis base; salts in acid. Gas phase: 3° > 2° > 1° > NH₃. Aqueous (solvation/sterics): (CH₃)₂NH > CH₃NH₂ > (CH₃)₃N > NH₃. Aromatic amines are weaker (lone pair delocalisation); +R/−I substituent effects apply.
Reactions (amines): Alkylation → higher amines/quaternary salts; acylation (1°,2°) → amides; carbylamine (1° + CHCl₃/KOH → isocyanide, foul smell); nitrous acid: 1° aliphatic → alcohol + N₂↑, 1° aromatic → stable diazonium at 273–278 K; Hinsberg separation (1° soluble sulphonamide; 2° insoluble; 3° no reaction).
Arylamines (aniline): Strongly activating o,p-directing; Br₂(aq) → 2,4,6-tribromoaniline; protection via acetylation for controlled EAS. No FC due to salt formation with AlCl₃.
Diazonium salts: Ar–N₂⁺X⁻ from ArNH₂ + NaNO₂/HCl at 273–278 K (diazotisation). Resonance-stabilised, used in situ (cold).
Reactions (diazonium): Sandmeyer/Gattermann (Cu(I)/Cu → ArCl/ArBr/ArCN); KI → ArI; HBF₄/heat → ArF; H₃PO₂ → Ar–H; hydrolysis → phenol; to –NO₂ (via Cu/NO₂⁻); azo coupling with phenols/arylamines → Ar–N=N–Ar′ dyes.

Important Figures

Pyramidal geometry at nitrogen in amines with lone pair — sp³ N: trigonal pyramidal geometry.

Gabriel phthalimide and Hofmann bromamide (loss of one carbon) — Gabriel (1° selective) & Hofmann degradation (−CO).

Diazotisation of aniline and azo coupling with phenol — Diazotisation (273–278 K) & azo dye formation.

Quick Summary

Remember selectivity (Gabriel 1°; Hinsberg separation), carbylamine test (1° only), aqueous basicity orders, protected EAS on aniline, and diazonium utility (Sandmeyer/Gattermann, KI, HBF₄, H₃PO₂, hydrolysis) plus azo coupling conditions.

Practice Quiz (10 MCQs)

1) Which is a secondary amine?

2) Best method to prepare a pure primary aliphatic amine (no 2°/3° mixture):

3) Correct aqueous basicity order for methyl amines:

4) Which gives the carbylamine (isocyanide) test with CHCl₃/KOH?

5) In Hinsberg’s test, which gives a soluble sulphonamide in alkali?

6) Treating aniline with NaNO₂/HCl at 273–278 K gives:

7) Diazotisation of aniline requires:

8) Replacement of N₂⁺ by Cl/Br/CN from ArN₂⁺X⁻ is done by:

9) Coupling of benzenediazonium chloride with phenol in alkaline medium gives mainly:

10) Product of Hofmann bromamide degradation of benzamide (Br₂/NaOH) is:

Downloads

Amines & Diazonium Quick Sheet (PDF) Named Reactions & Tests (PDF)

10 Biomolecules

Summative Weightage: High Updated: 09 Sep 2025

Chapter Notes

Carbohydrates: Polyhydroxy aldehydes/ketones or yield them on hydrolysis. Classes—mono/oligo (di- most common)/poly. Reducing vs non-reducing (all monosaccharides are reducing).
Key monosaccharides: D-Glucose (aldohexose) forms cyclic hemiacetal (α/β-D-glucopyranose); D-Fructose (ketohexose) forms furanose.
Disaccharides: Sucrose (non-reducing; hydrolysis → D-glucose + D-fructose; invert sugar), maltose (α-D-Glc + α-D-Glc; reducing), lactose (β-D-Gal + β-D-Glc; reducing).
Polysaccharides: Starch = amylose (α-1→4) + amylopectin (α-1→4, α-1→6 branches); cellulose = β-1→4 D-glucose; glycogen = highly branched (like amylopectin, more dense).
Proteins: Polymers of α-amino acids; peptide (-CO-NH-) link; levels—primary (sequence), secondary (α-helix/β-sheet, H-bonding), tertiary (3D fold), quaternary (subunits). Zwitterions; essential vs non-essential AAs.
Denaturation: Loss of secondary/tertiary structure and activity; primary sequence intact (e.g., egg white coagulation).
Enzymes: Mostly globular proteins; highly specific; lower activation energy.
Vitamins: Fat-soluble A, D, E, K (stored); water-soluble B-group, C (regular supply; except B₁₂ storage). Deficiency: A—night blindness; C—scurvy; D—rickets.
Nucleic acids: DNA/RNA = polynucleotides (sugar + base + phosphate). DNA: β-D-2-deoxyribose; bases A,G,C,T; double helix; A–T, G–C. RNA: β-D-ribose; A,G,C,U; usually single-stranded; mRNA, rRNA, tRNA.
Hormones: Endocrine messengers—steroids (e.g., cortisol, sex hormones), peptides (insulin), amino-acid derivatives (thyroxine, epinephrine); regulate metabolism, growth, stress, homeostasis.

Important Figures

Cyclic forms of D-glucose showing α and β anomers (pyranose) — D-Glucose as α/β-pyranose (hemiacetal at C1–C5).

Linkages in amylose/amylopectin vs cellulose — Starch: α-1→4 (± α-1→6) vs Cellulose: β-1→4.

DNA double helix base pairing and RNA components — DNA: A–T, G–C; RNA: A, U, G, C; ribose vs deoxyribose.

Quick Summary

Carbs: recognise reducing/non-reducing and key linkages (α-1→4/1→6 vs β-1→4). Proteins: peptide bond, four structural levels, denaturation. Enzymes: specific globular catalysts. Vitamins: ADEK (fat-sol), B/C (water-sol). Nucleic acids: nucleotide vs nucleoside, DNA pairing, RNA types. Hormones: peptide/steroid/AA-derived regulators.

Practice Quiz (12 MCQs)

1) D-Glucose is best described as:

2) Which statement about sucrose is correct?

3) The dominant cyclic form of D-glucose in solution is:

4) Branch points in amylopectin are due to:

5) Cellulose is composed of:

6) In neutral aqueous solution, amino acids predominantly exist as:

7) Protein secondary structure (α-helix/β-sheet) is stabilised mainly by:

8) Denaturation of proteins generally:

9) A nucleotide consists of:

10) Which base is present in RNA but not in DNA?

11) Correct vitamin classification is:

12) Which statement about enzymes is correct?

Downloads

Carbs–Proteins–Nucleic Acids Quick Sheet (PDF) Vitamins & Hormones One-Pager (PDF)