Addition, Elimination & Substitution - Organic Reactions & Mechanisms (8.2)

Question 1

What is an addition reaction?

Answer 1

Two molecules are joined together to form one product

Question 2

What is an elimination reaction?

Answer 2

A small molecule is removed from a larger molecule

Question 3

What is a substitution reaction?

Answer 3

One part of the molecule is swapped for another group

Question 4

What is a condensation reaction?

Answer 4

Two molecules join together forming the desired product & another small molecule

Question 5

What type of bond is involved in an addition reaction?

Answer 5

Double bond

Question 6

Name 3 types of addition reactions

Answer 6

• Hydrogenation
• Hydration
• Halogenation

Question 7

What is hydrogenation used to synthesise?

Answer 7

Margarine

Question 8

What is hydration used to synthesise?

Answer 8

Alcohol

Question 9

What is halogenation used to synthesise?

Answer 9

Haloalkanes

Question 10

What are the conditions required for hydrogenation?

Answer 10

• High temp

- Ni catalyst

Question 11

What are the conditions required for hydration?

Answer 11

• High temp & pressure
• Steam
• Strong acid catalyst

Question 12

What are the conditions required for halogenation?

Answer 12

Room temperature

Question 13

How can you test for the presence of alkenes?

Answer 13

An addition reaction using bromine water - bromine adds across the double bond
Orange -> colourless

Question 14

What happens in addition polymerisation?

Answer 14

• During polymerisation an alkene undergoes an addition reaction with itself to form a very long hydrocarbon chain
• The double bond in the monomer (alkene) opens up, joining the monomers together to make a polymer

Question 15

What conditions are required for polymerisation?

Answer 15

• Heat

- Catalyst

Question 16

Give the 2 types of elimination reactions

Answer 16

• Dehydration

- Elimination

Question 17

What is removed in dehydration?

Answer 17

Water

Question 18

What is commonly removed from an elimination reaction?

Answer 18

HX - hydrogen halide

Question 19

What are the conditions of a dehydration reaction?

Answer 19

reflux (boil)

w/ a concentrated acid catalyst

Question 20

What are the conditions of an elimination reaction when haloalkanes are the reactant?

Answer 20

Reflux (boil)

w/ a base in ethanol

Question 21

Name the reaction:

Alkane-> Alkene

Answer 21

Cracking

Question 22

Name the reaction:

Alkene -> Alkane

Answer 22

Hydrogenation

Question 23

Name the reaction:

Alkene -> Haloalkane

Answer 23

Addition

Question 24

Name the reaction:

Haloalkane -> Alkene

Answer 24

Elimination

Question 25

Name the reaction:

Alkene -> Alcohol

Answer 25

Hydration

Question 26

Name the reaction:

Alcohol -> Alkene

Answer 26

dehydration

Question 27

Give the 3 types of substitution reactions

Answer 27

• Free radical substitution
• Hydrolysis
• Halogenation

Question 28

What type of substitution reaction is this:

Alkane -> Haloalkane

Answer 28

Free radical substitution

Question 29

What molecule is involved in a hydrolysis?

Answer 29

Water

Question 30

What is synthesised in a halogenation reaction?

Answer 30

Haloalkane

Question 31

What conditions are required in free radical substitution?

Answer 31

UV light

Question 32

What conditions are required in hydrolysis?

Answer 32

Room temperature

Question 33

What conditions are required for halogenation?

Answer 33

Room temperature

Question 34

How can you test for haloalkanes?

Answer 34

• Warm the suspected haloalkane gently in water & add silver nitrate
• The free halide ion react w/ the silver ions to give a coloured precipitate

Question 35

How can you test for alcohols?

Answer 35

• Add phosphorus pentachloride to an alcohol
• White misty fumes of HCl will be released
• Universal indicator paper turns red (acidic fumes)