Phenol couples with benzene diazonium chloride in an alkaline solution to form p-hydroxy azobenzene (a red orange dye).

(i) Methanol do not have any effect on litmus paper whereas phenol turns blue litmus red.
(ii) Methanol do not give any colour with neutral FeCl₃ solution, whereas an aqueous solution of phenol gives violent colour with neutral FeCl₃ solution.

In phenol the electron density is increased in the benzene ring and hence the benzene ring is activated towards electrophilic substitution reaction and -OH group does not undergo substitution reaction like alcohol.

When ethylene glycol is treated with cone. H₂SO₄ two molecules of water are removed and the product formed is dioxane.

When ethylene reacts with alkaline KMnO₄ solution (Baeyer's reagent), it forms glycol (diol).

Glycol contains two hydroxyl groups which are able to form intermolecular hydrogen bonding made it much stronger. Hydrogen bond can be formed at both OH groups resulting in a polymeric structure.

This leads to high viscosity in glycol whereas in ethanol there is no strong intermolecular bydrogen bonding and it is less viscous.

Alcohols react with carboxylic acids in the presence of an acid to give esters.

Ethanol react with ammonia in presence of heated alumina or thoria catalyst at 633 K to form mixture of amines.

When C₂H₅OH (Ethanol) is treated with cone H₂SO₄ at 410 K, intermolecular dehydration take place and the product formed will be diethyl ether C₂H₅-O-C₂H₅.

(i) Alcohols are weaker acid than water because of +I effect of alkyl group. Hence, alcohols react only with electropositive metals evolving hydrogen.

(ii) The acid strength decreases in the order 1⁰>2⁰>3⁰ because of the electron releasing effect of the alkyl groups.

(i) Methanol (CH₃OH) is miscible with water because it is able to form hydrogen bonding with water due whereas iodo-methane (CH₃I)does not contain -OH group.
(ii) Since it is not able to form hydrogen bonding with water it is insoluble in water.