Organic Chemistry: Reactions and Synthesis

Question 1

How do we convert an alkene into an alkane? How much hydrogen do we need?

Answer 1

Add hydrogen. You need one hydrogen molecule for each double bond present.

Question 2

What is the reaction from an alkene to an alkane called?

Answer 2

Hydrogenation.

Question 3

What are the conditions for the reaction from an alkene to an alkane?

Answer 3

A temperature of 150°C and a Nickel catalyst.

Question 4

How do we convert a haloalkane into an alkane?

Answer 4

Add a hydrogen halide so the halogen is replaced by a hydrogen.

Question 5

How do we convert an alkane into an alkene? How much hydrogen do we get?

Answer 5

Remove hydrogen and you’ll get one molecule of hydrogen for each double bond created.

Question 6

What is the reaction from an alkane to an alkene called?

Answer 6

Dehydrogenation.

Question 7

What is the reaction from an alkane to a haloalkane called?

Answer 7

Free radical substitution.

Question 8

How do we convert an alkane into a haloalkane?

Answer 8

Substitute one hydrogen for one halogen.

Question 9

What are the conditions for the reaction from an alkane into a haloalkane.

Answer 9

UV light.

Question 10

What are the three steps for Free Radical Substitution?

Answer 10

Initiation, Propagation and Termination

Question 11

What happens in initiation in Free Radical Substitution? What is this process called?

Answer 11

UV light splits up two halogens into radicals. This is called homolytic fission.

Question 12

What happens in termination in Free Radical Substitution?

Answer 12

Any two free radicals combine to make a stable molecule.

Question 13

How do we convert an alcohol into an alkene?

Answer 13

Eliminate water from the alcohol.

Question 14

What is the reaction from an alcohol to an alkene called?

Answer 14

Dehydration.

Question 15

What are the conditions for the reaction from an alcohol to an alkene?

Answer 15

Catalyst of concentrated H₂SO₄

Question 16

How do we convert a haloalkane into an alkene?

Answer 16

Remove the halogens from the haloalkane to make an alkene.

Question 17

What is the reaction from a haloalkane to an alkene called?

Answer 17

Dehalogenation.

Question 18

How do we convert an alkene into an alcohol?

Answer 18

Add water to the alkene.

Question 19

What is the reaction from an alkene to an alcohol called?

Answer 19

Hydration.

Question 20

What are the conditions for the reaction from an alkene to an alcohol?

Answer 20

Steam at 300°C with concentrated phosphoric acid

Question 21

How do you convert an alkene into a haloalkane?

Answer 21

Add a halogen to an alkene.

Question 22

What is the reaction from an alkene to a haloalkane called?

Answer 22

Electrophilic Addition

Question 23

What happens in electrophilic addition?

Answer 23

• Electron pairs in the carbon double bond repel bromine, inducing dipole.
• π bond is attracted to the positive bromine dipole so the bromine dipoles come closer further repelling the σ bond.
• With the σ bond gone, the remaining electrons bond to one bromine creating a carbocation, where the other bromine will bond to.

Question 24

What are the conditions for electrophilic addition?

Answer 24

H₂SO₄

Question 25

How do we convert an alcohol to a haloalkane?

Answer 25

Replace the hydroxide ion with a halide ion.

Question 26

What are the conditions for the reaction from an alcohol to a haloalkane?

Answer 26

Concentrated H₂SO₄ and a spectator ion.

Question 27

How do we convert a haloalkane to an alcohol?

Answer 27

Replace the halide ion with a hydroxide ion

Question 28

What is the reaction from a haloalkane to an alcohol called?

Answer 28

Nucleophilic Substitution

Question 29

What happens in nucleophilic substitution ?

Answer 29

* The bromine will be more electronegative than the carbon so there are dipoles. * Electrons in the C-Br bond are repelled by the electrons from the new -OH bond. * Heterolytic fission takes place as the bromine atom gets both electrons from the carbon.

Question 30

What are the conditions for the reaction from a haloalkane into an alcohol

Answer 30

Ethanol and NaOH

Question 31

What do Alcohols produce when combusted?

Answer 31

Carbon Dioxide and Water

Question 32

What types of Alcohols can we oxidise?

Answer 32

Primary and Secondary.

Question 33

What mixture do we use to oxidise alcohols.

Answer 33

K₂Cr₂O₇ + H₂SO₄

Question 34

When an alcohol is oxidised, what is the colour change and why?

Answer 34

The colour will change from orange to green because the orange contains dichromate ions whilst the green contains chromium ions.

Question 35

What happens if we oxidate a primary alcohol using distillation?

Answer 35

The alcohol turns into water and an aldehyde.

Question 36

What happens if we oxidate a primary alcohol using reflux?

Answer 36

The alcohol will turn into a carboxylic acid and water.

Question 37

What is reflux?

Answer 37

Reflux is the continuous evaporating and condensing of a reaction mixture.

Question 38

What happens if we oxidate a secondary alcohol?

Answer 38

The alcohol will turn into a ketone.

Question 39

What happens if we oxidate a tertiary alcohol?

Answer 39

Nothing will happen as tertiary alcohols can't be oxidised.