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Oxygen-Containing Functional Groups: one-page cheat sheet

NEET Chemistry · Unit 17 · Organic Chemistry

ScoreChemby CSJ Sir
Weightage: 5–6 questions · 20–24 marks

1 · Alcohols

b.p.acids

>

alcohols

>

aldehydes, ketones

>

ethers

>

alkanes

Branchingbutan-1-ol 390 K

>

butan-2-ol 373 K

>

2-methylpropan-2-ol 356 K

HydroborationBH

_{3}

, then H

_{2}

_{2}

/ OH

^{-}

: anti-Markovnikov, no rearrangement

NaBH

_{4}

reduces aldehydes and ketones only

LiAlH

_{4}

also esters and acids

GrignardHCHO

\to

1^{\circ}

; RCHO

\to

2^{\circ}

; ketone

\to

3^{\circ}

Lucas

3^{\circ}

turbid at once;

2^{\circ}

in about 5 min;

1^{\circ}

none

2 · Phenols

Compound	p $K_{a}$
2,4,6-trinitrophenol (picric acid)	0.38
4-nitrophenol	7.1
2-nitrophenol	7.2
phenol	10.0
ethanol	15.9

Cumeneair oxidation, then dil. H

_{2}

_{4}

: phenol + acetone

KolbePhONa + CO

_{2}

(400 K, 4–7 atm)

\to

salicylic acid

Reimer–TiemannCHCl

_{3}

+ aq. NaOH via :CCl

_{2}

\to

salicylaldehyde

_{2}

watergives white 2,4,6-tribromophenol

Nitrationdil. HNO

_{3}

gives o- and p-nitrophenol; conc. gives picric acid

Testsneutral FeCl

_{3}

gives violet; phthalein dye test gives pink

3 · Ethers

WilliamsonRX + R′ONa; RX must be

1^{\circ}

, else elimination

HI cleavage

1^{\circ}

2^{\circ}

: S

_{N}

2 at the smaller alkyl group

3^{\circ}

alkylS

_{N}

1: tertiary iodide forms

AnisoleC

_{6}

_{5}

OCH

_{3}

+ HI

\to

phenol + CH

_{3}

4 · Carbonyl: nucleophilic addition

ReactivityHCHO

>

RCHO

>

ketone

Reagent	Product
HCN	cyanohydrin
NaHSO $_{3}$	bisulphite adduct
ROH, dry HCl	hemiacetal, acetal
NH $_{2}$ OH	oxime
NH $_{2}$ NH $_{2}$	hydrazone
2,4-DNP	orange-red ppt
semicarbazide	semicarbazone

5 · Named reactions

RosenmundRCOCl + H

_{2}

/ Pd–BaSO

_{4}

\to

RCHO

StephenRCN + SnCl

_{2}

/ HCl, then H

_{2}

\to

RCHO

DIBAL-Hester or nitrile

\to

aldehyde

Etardtoluene + CrO

_{2}

_{2}

\to

benzaldehyde

ClemmensenZn–Hg / HCl: C=O

\to

_{2}

Wolff–KishnerNH

_{2}

_{2}

/ KOH: C=O

\to

_{2}

PCC

1^{\circ}

alcohol stops at the aldehyde

6 · Aldol & Cannizzaro

Aldolneeds

α

-H; dilute NaOH; gives

β

-hydroxy carbonyl, then enal

2 CH_{3} CHO dil. NaOH CH_{3} CH(OH)CH_{2} CHO - H_{2} O CH_{3} CH = CHCHO

Cannizzarono

α

-H (HCHO, PhCHO); conc. NaOH; alcohol + acid salt

7 · Tests

Tollens'aldehydes: silver mirror

Fehling'saliphatic aldehydes: red Cu

_{2}

O; not benzaldehyde

IodoformCH

_{3}

CO– or CH

_{3}

CH(OH)–: yellow CHI

_{3}

NaHCO

_{3}

acids give CO

_{2}

; phenols do not

8 · Carboxylic acids

CF_{3} COOH > CCl_{3} COOH > CHCl_{2} COOH > NO_{2} CH_{2} COOH

NO_{2} CH_{2} COOH > FCH_{2} COOH > ClCH_{2} COOH > HCOOH > CH_{3} COOH

HVZRCH

_{2}

COOH + X

_{2}

/ red P

\to

α

-halo acid

Derivativesreactivity RCOCl

>

anhydride

>

ester

>

amide

Seen in NEET 2024

Propene, then BH $_{3}$ / H $_{2}$ O $_{2}$ , OH $^{-}$ , then PCC.

Propan-1-ol is oxidised only as far as propanal.

Seen in NEET 2021

Acetone + C $_{2}$ H $_{5}$ MgBr, then H $_{3}$ O $^{+}$ : tertiary alcohol 2-methylbutan-2-ol.

Seen in NEET 2025, 2020

Ester to aldehyde: DIBAL-H, then H $_{2}$ O.

Anisole + conc. HI: phenol + CH $_{3}$ I.

Seen in NEET 2026

C $_{8}$ H $_{8}$ O: 2,4-DNP positive, Fehling's negative, oxidises to benzoic acid.

A ketone: acetophenone, C $_{6}$ H $_{5}$ COCH $_{3}$ (it also gives the iodoform test).

Seen in NEET 2023

Cyclohexanone + HCN, then conc. H $_{2}$ SO $_{4}$ , then H $_{3}$ O $^{+}$ :

cyclohex-1-enecarboxylic acid (cyanohydrin, dehydration, nitrile hydrolysis).

Six traps to remember

Hydroboration–oxidation gives the anti-Markovnikov alcohol.
Williamson synthesis needs a primary alkyl halide.
Anisole with HI gives phenol and CH $_{3}$ I, never iodobenzene.
Fehling's test is negative for benzaldehyde.
Cannizzaro needs no $α$ -hydrogen; aldol needs at least one.
Electron-withdrawing groups raise acidity; alkyl groups lower it.

Oxygen-Containing Functional Groups: free one-page cheat sheet

1 · Alcohols

2 · Phenols

3 · Ethers

4 · Carbonyl: nucleophilic addition

5 · Named reactions

6 · Aldol & Cannizzaro

7 · Tests

8 · Carboxylic acids

Seen in NEET 2024

Seen in NEET 2021

Seen in NEET 2025, 2020

Seen in NEET 2026

Seen in NEET 2023

Six traps to remember