(c) Addition of Grignard reagents:   (refer Unit 7, Class XII) (d) Addition of alcohols:  Aldehydes react with one equivalent of
monohydric alcohol in the presence of dry hydrogen chloride
to yield alkoxyalcohol intermediate, known as hemiacetals,
which further react with one more molecule of alcohol to
give a gem-dialkoxy
compound known as
acetal as shown in the
reaction Ketones react with
ethylene glycol under
similar conditions to form
cyclic products known as
ethylene glycol ketals Dry hydrogen chloride
protonates the oxygen of
the carbonyl compounds
and therefore, increases
the electrophilicity of the
carbonyl carbon facilitating
Rationalised 2023-24
238
Chemistry
the nucleophilic attack of ethylene glycol