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General Organic Chemistry (GOC): concepts, formulas & solved PYQ-style examples

General organic chemistry decides how well you do in the whole of organic chemistry. Almost every reaction mechanism question is really a GOC question about which intermediate is more stable.

Always ask: does the group donate or withdraw electrons, and through which effect — inductive, resonance or hyperconjugation?

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Key concepts

Inductive effect

−I groups (NO₂, CN, halogens) withdraw, +I groups (alkyl) donate; fades with distance.

Resonance (mesomeric) effect

Delocalisation through π bonds; usually stronger than induction.

Hyperconjugation

α-C–H bonds stabilise carbocations and alkenes.

Reactive intermediates

Stability of carbocations, carbanions and free radicals.

Acidity and basicity

Stability of the conjugate base decides acid strength.

Formula sheet

Carbocation stability

3∘>2∘>1∘>CH3+3^\circ > 2^\circ > 1^\circ > \text{CH}_3^+

Acid strength rule

more stable conjugate base⇒stronger acid (lower pKa)\text{more stable conjugate base} \Rightarrow \text{stronger acid (lower p}K_a)

pKa relation

pKa=−log⁡Ka\text{p}K_a = -\log K_a

What PYQs keep asking

Patterns that repeat across previous-year JEE and NEET papers for this chapter.

  • Order of carbocation, carbanion or radical stability.
  • Acidic strength of substituted phenols and carboxylic acids.
  • Basic strength of amines (aliphatic vs aromatic, in water).
  • Identifying resonance structures and the most stable contributor.

Solved examples

Example 1

Arrange in increasing order of acidic strength: phenol, ethanol, p-nitrophenol, p-cresol.

  1. 1Ethanol: the ethoxide ion has no resonance, so it is the weakest acid.
  2. 2Phenoxide is resonance-stabilised; a methyl group (+I, hyperconjugation) in p-cresol destabilises it slightly.
  3. 3A para-NO₂ group (−R, −I) delocalises the negative charge further, so p-nitrophenol is the strongest.
Answer: Ethanol < p-cresol < phenol < p-nitrophenol
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Example 2

Arrange in increasing order of stability: CH₃⁺, CH₃CH₂⁺, (CH₃)₂CH⁺, (CH₃)₃C⁺.

  1. 1Each alkyl group donates electron density by +I effect and hyperconjugation.
  2. 2More α-hydrogens means more hyperconjugative structures: 9 for tert-butyl, 6 for isopropyl, 3 for ethyl, none for methyl.
  3. 3So stability rises from methyl to tertiary.
Answer: CH₃⁺ < CH₃CH₂⁺ < (CH₃)₂CH⁺ < (CH₃)₃C⁺
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Common traps

  • Treating halogens as electron donors in induction — they are −I (but +R).
  • Judging acidity from the acid itself instead of the stability of its conjugate base.
  • Ignoring the position of a substituent (ortho/para vs meta) on resonance.

Practise with

Chemical Equation BalancerChemical BondingChemical ThermodynamicsElectrochemistry11 Organic Chemistry practice questionsVideo solutions

FAQ

Which is stronger, resonance or inductive effect?

Generally resonance, because it moves charge through π systems; inductive effects weaken quickly with distance.

Why is phenol more acidic than ethanol?

The phenoxide ion is resonance-stabilised over the benzene ring; the ethoxide ion is not.

Is GOC important for NEET?

Yes — it underlies every organic chapter, and stability/acidity order questions are common.

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