CBSE Class 10 Answered

The hydroxyl group(OH) generally makes the alcohol molecule polar. Those groups can form hydrogen bonds to one another and to other compounds.

 This hydrogen bonding means that alcohols can be used as protic solvents. 

Alcohols, like water, can show either acidic or basic properties at the O-H group. With a pK_a of around 16-19 they are generally slightly weaker acids than water, but they are still able to react with strong bases such as sodium hydride or reactive metals such as sodium. The salts that result are called alkoxides, with the general formula RO^- M⁺.

Meanwhile the oxygen atom has lone pairs of nonbonded electrons that render it weakly basic in the presence of strong acids such as sulfuric acid. For example, with methanol:

Alcohols can also undergo oxidation to give aldehydes, ketones or carboxylic acids, or they can be dehydrated to alkenes.

They can react to form ester compounds, and they can (if activated first) undergo nucleophilic substitution reactions.

The lone pairs of electrons on the oxygen of the hydroxyl group also makes alcohols nucleophiles. For more details see thereactions of alcohols section below.

As one moves from primary to secondary to tertiary alcohols with the same backbone, the hydrogen bond strength, the boiling point,and the acidity typically decrease.