Carboxylic acids and their derivatives
Carboxylic acids and their
derivatives
Alcohols
•homologous series containing the OH hydroxyl
group.
•all names end in ol eg methanol, ethanol etc.
•isomers are possible for alcohols containing
3 or more carbons.
•label position of OH group so that it has the
lowest number
possible.
•polyhydric alcohols contain more than one OH
group eg
propane-
1,2,3,triol
OH groups attached to benzene rings are
called phenols.
Physical
properties of alcohols
•Molecules are polar, in the O-H bond, O is d- and H is d+
•Molecules have attractive forces
between the molecules called hydrogen bonds, not as strong as covalent bonds.
•Higher boiling point than corresponding alkanes.
•Hydrogen bonds form between alcohol and water
molecules therefore they are miscible / soluble.
•Long chain alcohols are less soluble.
Ethers
•General formula R-O-R’
•O-R’ alkoxy group substituted for H eg
•CH3-CH2-CH2-O-CH3 methoxypropane
•Longer hydrocarbon chain is parent alkane
for naming.
Physical
properties of ethers
•Molecules only slightly polar.
•No hydrogen on the oxygen atoms
to form hydrogen bonds – only weak forces of attraction between molecules.
•Boiling points similar to
corresponding alkane.
•Lower ethers, very volatile,
highly flammable.
•Only slightly soluble in water,
mix well with other non-polar solvents eg alkanes. (Like dissolves like).
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Chemistry for class 12 ...........
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