Orgo Final Review

What type of addition occurs in catalytic hydrogenation of alkenes

Syn addition (both H atoms add to the same face)

Which catalysts are used for hydrogenation of alkenes

Pt, Pd, Ni, Rh

What does a lower heat of hydrogenation indicate

Greater stability of the alkene

What is Markovnikov’s Rule

H adds to the carbon with more Hs; halogen/OH adds to more substituted carbon

What causes carbocation rearrangement

A shift (hydride or methyl) to form a more stable carbocation

What is the product of acid-catalyzed hydration of alkenes

An alcohol, following Markovnikov’s Rule

What is hydroboration-oxidation

Anti-Markovnikov, syn addition of H and OH to a double bond (no rearrangement)

What is the hybridization of a carbon in a triple bond

sp-hybridized (linear geometry)

Why are terminal alkynes more acidic than alkenes and alkanes

Higher s-character of the C–H bond (sp hybridized)

How is an acetylide ion formed

Deprotonation of a terminal alkyne with a strong base (e.g., NaNH₂)

What is the role of acetylide ions in synthesis

Nucleophile in SN2 alkylation reactions

How are alkynes synthesized from dihalides

Double elimination with NaNH₂

What does Lindlar’s catalyst produce from alkynes

Cis-alkenes (partial hydrogenation)

How do you make a trans-alkene from an alkyne

Use Na/NH₃ (dissolving metal reduction)

What is the product of hydration of an alkyne using HgSO₄ and H₂SO₄

A ketone (via enol tautomerization)

What product forms when 1 equivalent of X₂ reacts with an alkyne

Dihaloalkene

What are the ozonolysis products of alkynes

Carboxylic acids

What is a radical

A species with one unpaired electron

What is the trend in alkyl radical stability

3° > 2° > 1° > methyl

What is bond dissociation energy (BDE)

Energy required for homolytic cleavage; lower BDE = more stable radical

How is radical halogenation initiated

UV light or heat splits Cl₂ into two Cl• radicals

What are the steps of a radical chain reaction

Initiation, Propagation, Termination

What happens during propagation in methane chlorination

Cl• abstracts H from CH₄ → CH₃• + HCl → CH₃• reacts with Cl₂ to form CH₃Cl + Cl•

Why is bromination more selective than chlorination

Forms more stable radicals; higher activation energy = greater selectivity

When is syn addition observed

Hydrogenation and hydroboration-oxidation

Which reactions follow anti-Markovnikov addition

Hydroboration-oxidation and radical HBr addition with peroxides

What is tautomerization

Conversion of an enol to a more stable keto form

How does Le Châtelier’s Principle affect hydration reactions

Adding water drives equilibrium toward alcohol formation

How can a terminal alkyne be synthesized from an alkene

Add Br₂ to alkene → dihalide → double elimination with NaNH₂