NCERT Book Class 12 Chemistry Chapter 7 Alcohols, Phenols and Ethers

Unit

Objectives Alcohols
Alcohols,, Phenols
7
After studying this Unit, you will be
able to
• name alcohols, phenols and
and Ether
therss
ethers according to the IUPAC
system of nomenclature;
Alcohols, phenols and ethers are the basic compounds for the
• discuss the reactions involved in
formation of detergents, antiseptics and fragrances, respectively.
the preparation of alcohols from
alkenes, aldehydes, ketones and
carboxylic acids; You have learnt that substitution of one or more
• discuss the reactions involved in hydrogen atom(s) from a hydrocarbon by another atom
the preparation of phenols from or a group of atoms result in the formation of an entirely
haloarenes, benzene sulphonic new compound having altogether different properties
acids, diazonium salts and and applications. Alcohols and phenols are formed
cumene;
when a hydrogen atom in a hydrocarbon, aliphatic and
• discuss the reactions for aromatic respectively, is replaced by –OH group. These
preparation of ethers from
classes of compounds find wide applications in industry
(i) alcohols and (ii) alkyl halides
and sodium alkoxides/aryloxides; as well as in day-to-day life. For instance, have you
• correlate physical properties of
ever noticed that ordinary spirit used for polishing
alcohols, phenols and ethers with wooden furniture is chiefly a compound containing
their structures; hydroxyl group, ethanol. The sugar we eat, the cotton
• discuss chemical reactions of the used for fabrics, the paper we use for writing, are all
three classes of compounds on made up of compounds containing –OH groups. Just
the basis of their functional think of life without paper; no note-books, books, news-
groups. papers, currency notes, cheques, certificates, etc. The
magazines carrying beautiful photographs and
interesting stories would disappear from our life. It
would have been really a different world.
An alcohol contains one or more hydroxyl (OH)
group(s) directly attached to carbon atom(s), of an
aliphatic system (CH3OH) while a phenol contains –OH
group(s) directly attached to carbon atom(s) of an
aromatic system (C6H5OH).
The substitution of a hydrogen atom in a
hydrocarbon by an alkoxy or aryloxy group
(R–O/Ar–O) yields another class of compounds known
as ‘ethers’, for example, CH3OCH3 (dimethyl ether). You
may also visualise ethers as compounds formed by