Alcohol phenol and ether class 12 ncert solutions

Phenols Phenol (also called carbolic acid) is an aromatic organic compound with the molecular formula C₆Hâ‚…OH. It is a white crystalline solid that is volatile. The molecule consists of a phenyl group (−C₆Hâ‚…) bonded to a hydroxy group (−OH). Mildly acidic, it requires careful handling because it can cause chemical burns. Phenols— Mono, Di and Trihydric Phenols Depending on the number of hydroxyl groups attached, phenols can be classified into three types. • (i) Monohydric phenols: They contain one -OH group. • (ii) Dihydric phenols: They contain two -OH groups. They may be ortho-, meta- or para- derivative. • (iii) Trihydric phenols: They contain three -OH groups. Ethers are classified as simple or symmetrical, if the alkyl or aryl groups attached to the oxygen atom are the same, and mixed or unsymmetrical, if the two groups are different. Diethyl ether, Câ‚‚Hâ‚…OCâ‚‚Hâ‚…, is a symmetrical ether whereas Câ‚‚Hâ‚…OCH₃ and Câ‚‚Hâ‚…OC₆Hâ‚… are unsymmetrical ethers. Boiling Points The boiling points of alcohols and phenols increase with increase in the number of carbon atoms (increase in van der Waals forces). In alcohols, the boiling points decrease with increase of branching in carbon chain (because of decrease in van der Waals forces with decrease in surface area).