General Organic Chemistry (GOC) 

1) Basics of Organic Chemistry

• Organic compounds: hydrocarbons and their derivatives.
• Vital force theory: Organic compounds formed only in living systems (Berzelius).
• Wöhler synthesis: Urea prepared from inorganic salts — disproved vital force theory.
• Classification: Aliphatic / Cyclic → Saturated / Unsaturated → Aromatic / Alicyclic.

2) Aromaticity (Hückel Rule)

• Aromatic compounds are planar, cyclic, conjugated.
• Must obey (4n + 2) π electrons.
• Show electrophilic substitution and resist addition.
• Examples: Benzene (6π), Naphthalene (10π).
• Heteroaromatics: Pyridine, Pyrrole, Furan, Thiophene.

3) Nomenclature Rules (Quick Recap)

• Lowest locant rule: first substituent gets lowest number.
• Lowest sum rule: lowest total of substituent positions.
• First point of difference: lower number at first mismatch preferred.
• Substituents written in alphabetical order.
• Complex substituents written in brackets and numbered separately.

4) Functional Group Priority (High → Low)

5) Structural Isomerism

• Chain isomerism: different carbon skeleton.
• Positional isomerism: different position of bond or group.
• Functional isomerism: different functional groups.
• Metamerism: different alkyl groups on either side of same functional group.
• Ring-chain isomerism: open chain vs cyclic structure.
• Tautomerism: dynamic equilibrium (e.g., keto–enol).

6) Tautomerism

• Interconversion due to shift of H-atom and π-electrons.
• Keto–enol tautomerism: aldehydes & ketones with α-hydrogen.
• β-diketones show higher enol content due to chelation.
• Also seen in nitro–aci and nitroso–oxime systems.

7) Electronic Effects

Inductive Effect (I)

• Permanent effect through σ-bonds.
• –I groups: –NO₂, –COOH, –F, –Cl, –Br.
• +I groups: Alkyl groups.

Mesomeric Effect (M)

• Delocalisation of π-electrons.
• +M: –OH, –OR, –NH₂ (ortho/para directors).
• –M: –NO₂, –CHO, –COOH (meta directors).

Electromeric Effect (E)

• Temporary effect in presence of attacking reagent.
• Occurs in compounds with π-bonds.

8) Resonance

• Delocalisation of electrons in conjugated systems.
• Actual structure is a resonance hybrid.
• More resonance → more stability.
• Bond order = average of resonating structures.
• All resonating structures must have same atomic positions.

9) Reaction Intermediates

Free Radicals

• Formed by homolytic cleavage.
• sp² hybridised, highly reactive.
• Stability: 3° > 2° > 1° > methyl.

Carbocations

• Formed by heterolytic cleavage.
• Electron deficient.
• Stability: 3° > 2° > 1° > methyl.

Carbanions

• Electron rich species.
• Stability increases with electron-withdrawing groups.

Carbenes

• Incomplete octet.
• Exist as singlet or triplet.

10) Types of Organic Reactions

• Addition: electrophilic, nucleophilic, radical.
• Elimination: α, β, γ eliminations.
• Substitution: SN, SR, SE reactions.
• Condensation: two molecules combine with loss of small molecule.
• Rearrangement: carbon skeleton rearranges.
• Polymerisation: monomers → polymers.