What is esterification? Explain with examples.

(N/A) Esterification: The reaction of alcohols and phenols with carboxylic acids,acid chlorides,and acid anhydrides to form esters is known as esterification.
$(i)$ Reaction of alcohols/phenols with carboxylic acids $(R'COOH)$: This reaction involves the cleavage of the $O-H$ bond of the alcohol or phenol.
$(ii)$ Reaction of alcohols/phenols with acid anhydrides: In this reaction,the $O-H$ bond of the alcohol or phenol breaks to form $-OCOR'$. This reaction is carried out in the presence of a small amount of concentrated $H_2SO_4$ and is reversible.
$(iii)$ Reaction of alcohols/phenols with acid chlorides $(R'COCl)$: In this reaction,the $O-H$ bond breaks to form $-OCOR'$. This reaction is carried out in the presence of a base like pyridine to neutralize the $HCl$ produced,which shifts the equilibrium to the right (product side).
$(b)$ Acetylation: Acetylation is a specific type of esterification where the $-OH$ group is converted into $-COCH_3$. It involves the introduction of an acetyl group $(CH_3CO-)$ into alcohols and phenols. Acetylation of salicylic acid produces aspirin,which is a well-known analgesic,anti-inflammatory,and antipyretic drug.