The greater the pKa
value, the weaker the
acid Rationalised 2023-24
208
Chemistry
Pyridine
R/Ar
+R’
l
OH
COC
R/ArOCOR + HCl
’
The reaction with carboxylic acid and acid anhydride is carried
out in the presence of a small amount of concentrated sulphuric
acid The reaction is reversible, and therefore, water is removed as
soon as it is formed The reaction with acid chloride is carried out in
the presence of a base (pyridine) so as to neutralise HCl which is
formed during the reaction