Unit 4 - Topic 1 - Organic Reactions and Reaction Pathways*

Question 1

Define a substitution reaction, and state which compounds undergo substitution

Answer 1

Atoms are exchanged for others

Only saturated compounds - 2 types:
1. Alkanes
2. Haloalkanes

Question 2

Explain substitution reaction of alkanes

Answer 2

Alkane + Halogen —> haloalkane

Reaction requirements:
UV light

If enough halogen available - further reactions can occur - resulting in all H of alkane substituted by a halogen atom

The different products (after each step of substitution - w/ different number of halogens) have different boiling points - thus can be separated by fractional distillation

Question 3

*Explain substitution reaction of haloalkanes

Answer 3

Can undergo substitution reactions to form a dihaloalkane, amine, nitrile or an alcohol

Halogen & carbon bond means = polar bond (large electronegativity difference)

Other species can be substituted for the halogen

Question 4

Define an addition reaction and list the types

Answer 4

Is when an alkene reacts and the double bond breaks

3 types:
1. Hydrogenation
2. Halogenation
3. Hydration

Question 5

Explain hydrogenation addition reaction

Answer 5

(form of reduction)

Alkene + Hydrogen —> Akane

Reaction requirements:
Metal catalyst - ie. Ni

Question 6

Explain halogenation addition reaction

Answer 6

Alkene/alkyne + Halogen —> Haloalkane

Question 7

Explain hydration addition reaction

Answer 7

Alkene + Water —> Alcohol

Reaction requirements:
High temperature (~300°C), high pressure (~60atm), catalyst (trace strong acid ie. HCl)

Question 8

Define an elimination reaction

Answer 8

Elimination reactions are when 2 molecules are removed to make a double bond

Question 9

Define a condensation reaction

Answer 9

Condensation reactions are when 2 molecules combine to form a larger molecule and produce water