Organic Chemistry Reaction

Question 1

Aldol Condensation

Answer 1

Reagents: Dil. NaOH or KOH
Intermediate: Enolate ion
What Happens: Two aldehyde/ketone molecules condense if they have α-hydrogens.
Product: β-Hydroxy aldehyde/ketone → α,β-unsaturated compound after dehydration

Question 2

Cannizzaro Reaction

Answer 2

Reagents: Conc. NaOH
Intermediate: Alkoxide ion, carboxylate ion
What Happens: One molecule of non-enolizable aldehyde is reduced, another is oxidized.
Product: Alcohol + Carboxylic acid salt

Question 3

Friedel–Crafts Alkylation

Answer 3

Reagents: Alkyl halide, anhydrous AlCl₃
Intermediate: Carbocation (R⁺)
What Happens: Alkyl group is introduced into the benzene ring.
Product: Alkylbenzene

Question 4

Friedel–Crafts Acylation

Answer 4

Reagents: Acyl halide, AlCl₃
Intermediate: Acylium ion (RCO⁺)
What Happens: Acyl group substitutes on benzene ring.
Product: Aromatic ketone (e.g., acetophenone)

Question 5

Kolbe Reaction

Answer 5

Reagents: Sodium phenoxide, CO₂, H⁺
Intermediate: Resonating phenoxide ion
What Happens: CO₂ adds to ortho-position of phenol.
Product: Salicylic acid

Question 6

Reimer–Tiemann reaction

Answer 6

Reagents: Phenol, CHCl₃, NaOH
Intermediate: Dichlorocarbene (:CCl₂)
What Happens: Formyl group (-CHO) introduced ortho to –OH.
Product: o-Hydroxybenzaldehyde

Question 7

Perkin Reaction

Answer 7

Reagents: Aromatic aldehyde, Acetic anhydride, Sodium acetate
Intermediate: Enolate ion
What Happens: Condensation gives α,β-unsaturated acid.
Product: Cinnamic acid-type compound

Question 8

Hell–Volhard–Zelinsky Reaction (HVZ)

Answer 8

Reagents: Carboxylic acid, Br₂, PBr₃
Intermediate: Acyl bromide and enol
What Happens: α-H of acid replaced with Br.
Product: α-Bromo acid

Question 9

Gabriel Phthalimide Synthesis

Answer 9

Reagents: Phthalimide, KOH, Alkyl halide
Intermediate: Potassium phthalimide
What Happens: Used to prepare primary amines.
Product: Primary amine (R–NH₂)

Question 10

Hoffmann Bromamide Degradation

Answer 10

Reagents: Amide, Br₂, NaOH
Intermediate: Isocyanate
What Happens: Amide loses one carbon and forms primary amine.
Product: Primary amine

Question 11

Carbylamine Reaction

Answer 11

Reagents: CHCl₃, Alcoholic KOH, 1° Amine
Intermediate: Dichlorocarbene
What Happens: Forms foul-smelling isocyanide.
Product: Isocyanide (R–NC)

Question 12

Sandmeyer Reaction

Answer 12

Reagents: CuCl/CuBr, HCl/HBr, Diazonium salt
Intermediate: Diazonium salt
What Happens: Replaces –N₂⁺ group with Cl, Br, or CN.
Product: Aryl halide or nitrile

Question 13

Gattermann Reaction

Answer 13

Reagents: Cu powder, HCl, Diazonium salt
Intermediate: Diazonium salt
What Happens: Replaces –N₂⁺ with hydrogen.
Product: Benzene derivative (C₆H₆)

Question 14

Wurtz Reaction

Answer 14

Reagents: Alkyl halides, Na metal, Dry ether
Intermediate: Free radical
What Happens: Two alkyl halides couple to form a longer chain.
Product: Alkane

Question 15

Wurtz–Fittig Reaction

Answer 15

Reagents: Aryl halide, Alkyl halide, Na, Dry ether
Intermediate: Free radicals
What Happens: Coupling of aryl and alkyl groups.
Product: Alkyl arene (e.g., toluene)

Question 16

Beckmann Rearrangement

Answer 16

Reagents: Ketoxime, Acid catalyst (H₂SO₄, PCl₅)
Intermediate: Nitrenium ion
What Happens: Ketoxime rearranges to amide.
Product: Amide

Question 17

Baeyer–Villiger Oxidation

Answer 17

Reagents: Ketone, Peracid (e.g., mCPBA)
Intermediate: Criegee intermediate
What Happens: Oxygen inserts between carbonyl and alkyl group.
Product: Ester

Question 18

Pinacol–Pinacolone Rearrangement

Answer 18

Reagents: Pinacol (vicinal diol), H₂SO₄
Intermediate: Carbocation
What Happens: Rearrangement of diol under acid.
Product: Pinacolone (ketone)