H
H
+
H
-
H
COMPARISON OF PHENOL AND ETHANOL
Phenol and ethanol are both hydroxy compounds as they both contain the –OH group. The difference is that, in phenol, this group is bonded to a benzene ring whereas in ethanol it is bonded to an alkyl group.
With water
(i)Ethanol and water are miscible in all proportions. Both molecules contain the –OH group (and the ethanol molecule is small) so hydrogen bonding can occur between them.
Ethanol is not an acid as it does not donate a proton to water.
(ii) Phenol is only slightly soluble in water. If enough phenol is added, two liquid layers are produced: one is a saturated solution of phenol in water; the other is a saturated solution of water in phenol. Although both molecules contain the –OH group the presence of the non-polar benzene ring reduces the solubility of phenol.
Phenol is a weak acid as it partially ionizes in water. The C
6
H
5
O
-
ion produced is called the phenoxide ion. This ion is stabilized by electron delocalization of the 2p z
electrons of the oxygen atom with the charge cloud of the benzene ring.
-
O H + H O H O +
H
O
H
H
+
With sodium hydrogen carbonate
(i) Ethanol does not react (as it is not an acid)
(ii) Phenol does not react (as it is not a strong enough acid)

2 2
2 2
+
Na H
+
Na H
-
O H
-
O H
With sodium hydroxide
(i) Ethanol does not react
(ii) The above equilibrium is driven to the right as the added OH
-
ions remove H
3
O
+ ions. Therefore the above equilibrium is driven to the right and more phenol dissolves, giving a colourless solution. If acid is added to the resulting solution, the two layers reform as the equilibrium is driven back to the left .
With sodium
(i) Sodium dissolves in ethanol, forming sodium ethoxide , and hydrogen is produced.
H H H H
-
2
H C C O H
+
2 Na
2
H C C O
+
2 Na
+ +
H H H H
(ii) A similar, but more vigorous reaction, occurs as phenol is a stronger acid than ethanol. Sodium phenoxide and hydrogen are produced
H H
-
2
O H + 2 Na
2
O + 2 Na
+ + H H
With bromine water
(i) Ethanol will not react with bromine water, but will, under the right conditions, undergo nucleophilic substitution with Br
-
, giving bromoethane.
(ii) Phenol decolorizes bromine water and a white ppt forms. The reaction is electrophilic substitution. No halogen carrier is needed
(unlike benzene) as the OH group makes the ring more susceptible to electrophilic attack. The OH group directs further substitution to the 2, 4 and 6 positions.

Br O
H
H
Br
Br Br Br O H
H
Br O
H
O H +
3
Br Br
H Br
+
3
H Br
H
Br
With neutral iron(III)chloride solution
(i) Ethanol does not react
(ii) Phenol reacts giving a purple -coloured product. The colour is due to the formation of a complex ion in which the O atom of the phenol molecule forms a dative covalent bond with the Fe
3+
ion. This test is sometimes used to test for the presence of phenol.