$A$ key step in the hydrolysis of acetamide in aqueous acid proceeds by nucleophilic addition of

The role of conc. $H_2SO_4$ in the esterification process is

The product $(D)$ in the following reaction sequence is: $HOCH_2CH_2CH_2COOCH_2CH_3$ $\xrightarrow{PCC} (A)$ $\xrightarrow[{(1 \ molar \ equivalent)}]{H_2C=CHMgBr} (B)$ $\xrightarrow{NH_4Cl/H_2O} (C)$ $\xrightarrow[H_2O]{KOH}$ $\xrightarrow{H_3O^{+}}$ $\xrightarrow[pyridine]{(CH_3CO)_2O} (D)$

Give reactions of carboxylic acids in which $C-OH$ bond breaks. $OR$ Give methods of preparation for $(a)$ anhydride $(b)$ ester $(c)$ acid chloride and $(d)$ amide from carboxylic acids.

$CH_3-CH_2-COOH$ $\xrightarrow{Cl_2/Fe} X$ $\xrightarrow{\text{Alcoholic } KOH} Y$. Compound $Y$ is:

The decreasing order of the rate of alkaline hydrolysis for the following esters is:
$I: C_6H_5COOC_2H_5$
$II: p-Cl-C_6H_4COOC_2H_5$
$III: p-NO_2-C_6H_4COOC_2H_5$
$IV: p-CH_3O-C_6H_4COOC_2H_5$