Phenol

Question 1

Reaction with Na

Answer 1

Observation: Effervescence
Sodium phenoxide and hydrogen is formed

Question 2

Compare the relative acidities of water, ethanol and phenol

Answer 2

Ethanol is less acidic than water because the ethoxide ion has an alkyl group which is electron pushing, the intensity of the negative charge on the O- increases thus equilibrium will shift to the left and concentration of H+ ion decreases. Phenol is more acidic than water, because when the phenoxide ion is formed, the lone pairs of electrons on the oxygen tend to get delocalised on the ring and the intensity of the negative charge is decreased, the ion is stabilised

Question 3

Reaction with NaOH

Answer 3

Observation: Phenol dissolves

Question 4

Nitration

Answer 4

Reagent: dilute HNO3
Condition: R.T
Type of reaction: Electrophilic substitution
Nitrophenol is produced

Question 5

Why is the benzene ring more reactive towards electrophiles in phenol?

Answer 5

The OH group activates the benzene ring by increasing the electron density on the ring due to delocalisation of electrons of oxygen onto the ring

Question 6

Bormination

Answer 6

Reagents: Br2(aq)
Conditions: R.T
Type of reaction: Electrophilic substitution
Expected product: 2,4,6-tribromophenol unless monosubstitution is mentioned
Observation: Bromine is decolourised and a white solid is formed

Question 7

Azo-dye formation

Answer 7

Reagent: benzenediazonium ion (salt)
Condition: NaOH(aq)
Type of reaction: coupling
Azo-dye is produced

Question 8

Reaction that produces phenol

Answer 8

Reaction with phenylamine with HNO2 or NaNO2 and dilute acid