Phenol

Question 1

Why phenol undergoes electrophilic sub reactions more readily

Answer 1

• lone pair of electrons from O is delocalised into ring
• delocalisation from overlapping p orbitals extends from ring to oxygen atom
• weakens OH bond so phenol is able to donate H+ ion(weak acid)
• stabilised phenoxide ion C6H5O-
  -increases electron density in delocalised pi system likes electrophilic sub

Question 2

Reaction with NaOH

Answer 2

produces salt and water

O-Na+ + H2O

Question 3

Bromination

Answer 3

Conditions: dilute HNO3
O- on phenol ion induced dipole on Br2 bond

Electrophilic sub occurs at 2,4,6 on ring

Question 4

2,4 electron releasing side chain

Answer 4

CH3
OH
NH2

Question 5

3,5 electron withdrawing side chain

Answer 5

NO2
C=O
COOH

Question 6

Electron releasing

Answer 6

increase electron density of ring
increase attraction for electrophile
rate of reaction increases

Question 7

Electron withdrawing

Answer 7

Decrease electron density of ring
Decrease attraction for electrophile
rate of reaction decreases