Give explanation of following :
(i) During the preparation of esters from a carboxylic acid and an alcohol in the easter should be removed as soon as it is formed.

Explanation

i.
Due to the presence of three (Me) groups at `alpha`-positions w.r.t. the `(C=O)` group in (II), the nucleophilic attack by `C^()N` does not occur due to steric hindrance. But there is no steric hindrance in (I), therefore, nucleophilic attack by `CN^(Θ)` readily takes place and hence (III) is obtained in good yield.
ii. N/A
iii. The reaction is reversible, therefore, to shift the equilibrium in the forward direction, the water or the ester formed should be removed as fast as it is formed.
`RCOOH + R'OH underset(H_(2)SO_(4))hArrunderset("Ester")(RCOOR'+H_(2)O)`