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General Organic Chemistry: one-page cheat sheet

NEET Chemistry · Unit 14 · Organic Chemistry

ScoreChemby CSJ Sir
Weightage: 3–4 questions · 12–16 marks

1 · Hybridisation of carbon

Type	Shape	Angle	$s$ -char.
$s p^{3}$	tetrahedral	109.5°	25%
$s p^{2}$	trigonal planar	120°	33%
$s p$	linear	180°	50%

electronegativity: C (s p) > C (s p^{2}) > C (s p^{3})

DBE = \frac{2 C + 2 + N - H - X}{2}

2 · IUPAC naming

COOH > SO_{3} H > COOR > COCl > CONH_{2} > CN

CN > CHO > C=O > OH > NH_{2} > C=C > C \equiv C

Prefix onlyhalogens, nitro, alkoxy, alkyl, phenyl

Numberinglowest locant at the first point of difference; a tie goes to the alphabetically first substituent

The longest chain containing the principal group is the parent.

3 · Suffixes & carbon types

Group	Suffix
carboxylic acid	-oic acid
ester	-oate
amide	-amide
nitrile	-nitrile
aldehyde	-al
ketone	-one
alcohol	-ol
amine	-amine

Carbon types1°, 2°, 3° by carbon neighbours; 4° has four

4 · Isomerism

Type	Example
Chain	pentane, isopentane, neopentane
Position	propan-1-ol, propan-2-ol
Functional	ethanol, methoxymethane
Metamerism	C $_{2}$ H $_{5}$ OC $_{2}$ H $_{5}$ , CH $_{3}$ OC $_{3}$ H $_{7}$
Tautomerism	keto–enol
Stereo	geometrical; optical

5 · Electronic effects

- I

orderNO

_{2}

>

>

COOH

>

>

>

>

>

>

_{6}

_{5}

+ I

order

t

-Bu

>

i

-Pr

>

>

+ R

OH, OR, NH

_{2}

, halogens (ortho, para)

- R

_{2}

, CHO, C=O, CN, COOH (meta)

Hyperconj.

σ_{C-H}

delocalised into an adjacent empty

p

π

; more

α

hydrogens, more stable

6 · Reactive intermediates

Carbocation

3^{\circ} > 2^{\circ} > 1^{\circ} > CH_{3}^{+}

; allyl and benzyl are resonance-stabilised

Free radical

3^{\circ} > 2^{\circ} > 1^{\circ} > CH_{3} \cdot

Carbanion

CH_{3}^{-} > 1^{\circ} > 2^{\circ} > 3^{\circ}

;

- I

and

- M

groups stabilise

Shapecarbocation

s p^{2}

planar; carbanion

s p^{3}

pyramidal

7 · Acidity orders

HCOOH > CH_{3} COOH > C_{2} H_{5} COOH > (CH_{3})_{3} CCOOH

CCl_{3} COOH > CHCl_{2} COOH > CH_{2} ClCOOH > CH_{3} COOH

Halo acidsFCH

_{2}

COOH

>

ClCH

_{2}

COOH

>

BrCH

_{2}

COOH

>

ICH

_{2}

COOH

Phenols

p

-nitrophenol

>

phenol

>

p

-cresol; phenol

>

alcohol

8 · Reagents & reactions

Homolysisfree radicals; Heterolysis: ions

ElectrophilesH

^{+}

, NO

_{2}^{+}

, BF

_{3}

, AlCl

_{3}

, carbocations

NucleophilesOH

^{-}

, CN

^{-}

, NH

_{3}

, H

_{2}

O, ROH

Typessubstitution, addition, elimination, rearrangement

9 · Resonance & aromaticity

Stabilitymore resonance structures, more stable; avoid charge separation

Aromaticplanar, cyclic, fully conjugated,

(4 n + 2) π

electrons

Examplesbenzene (6), tropylium cation (6), cyclopentadienyl anion (6)

10 · Stereo basics

Chiral Cfour different groups

stereoisomers = 2^{n} (n stereocentres, no symmetry)

Mesointernal mirror plane; optically inactive

Racemic50:50 mixture of enantiomers, no net rotation

Seen in NEET 2026

CH_{3} CH_{2} CH (C_{2} H_{5}) CH_{2} CH (CH_{3}) CH_{2} CH_{3}

Seven-carbon chain; the tie in locants (3, 5) goes to ethyl: 3-ethyl-5-methylheptane.

Seen in NEET 2026

Metamers: CH $_{3}$ OCH $_{2}$ CH $_{2}$ CH $_{3}$ (methoxypropane) and C $_{2}$ H $_{5}$ OC $_{2}$ H $_{5}$ (ethoxyethane).

Seen in NEET 2024

C $_{6}$ H $_{14}$ with two tertiary carbons: 2,3-dimethylbutane.

Seen in NEET 2025

Acid strength falls as alkyl groups ( $+ I$ ) are added: HCOOH is the strongest.

Six traps to remember

Electronegativity of carbon rises with $s$ -character: $s p > s p^{2} > s p^{3}$ .
When locant sets tie, the alphabetically first substituent gets the lower number.
Metamers differ in the alkyl groups on either side of the same functional group.
Carbocation stability: $3^{\circ} > 2^{\circ} > 1^{\circ}$ ; carbanion order is the reverse.
Halogens are $- I$ but $+ R$ : deactivating, yet ortho/para directing.
HCOOH is a stronger acid than CH $_{3}$ COOH; $+ I$ groups weaken acids.

General Organic Chemistry: free one-page cheat sheet

1 · Hybridisation of carbon

2 · IUPAC naming

3 · Suffixes & carbon types

4 · Isomerism

5 · Electronic effects

6 · Reactive intermediates

7 · Acidity orders

8 · Reagents & reactions

9 · Resonance & aromaticity

10 · Stereo basics

Seen in NEET 2026

Seen in NEET 2026

Seen in NEET 2024

Seen in NEET 2025

Six traps to remember