6.1.3 Substituted Benzene Rings

Question 1

What are the properties of electron-donating side chains?

Answer 1

• Increases the electron density of the ring, therefore increasing the attraction for the electrophile.
• Rate of reaction increases.

Question 2

What are the properties of electron-withdrawing side chains?

Answer 2

• Decreases the electron density of the ring, therefore decreasing the attraction for the electrophile.
• Rate of reaction decreases.

Question 3

What are the activating groups for electron-donating side chains?

Answer 3

• OH and NH2.

Question 4

What are the deactivating groups for electron-withdrawing side chains>

Answer 4

• NO2.

Question 5

What positions do electron-donating side chains promote?

Answer 5

• 2 and 4.

Question 6

What positions do electron-withdrawing side chains promote?

Answer 6

• 3.

Question 7

What are the properties of phenols?

Answer 7

• Weakly acidic
• Reacts with sodium and sodium hydroxide
• Less acidic than carboxylic acids
• Does not react with sodium carbonate

Question 8

What observations can be made when phenol reacts with bromine?

Answer 8

• Bromine is colourised and a white precipitate is formed.

Question 9

Why does phenol react more readily with phenol than benzene?

Answer 9

• The lone pair of electrons on oxygen is partially delocalised into this ring.
• This increases the electron density of the ring.
• Phenol can polarise and attract electrophiles more than benzene.

Question 10

What organic compounds can phenol not react with?

Answer 10

• Esters
• Carboxylic acids.

Question 11

What organic compounds can phenol react with?

Answer 11

• Acyl chlorides
• Acid anhydrides.

Question 12

Why is nitrobenzene less reactive to electrophiles than benzene?

Answer 12

• NO2 is electron withdrawing.
• This decreases the electron density of the benzene ring.
• The electrophile is less polarised.