$B.$ Neutral $FeCl _3$ solution is used to test phenolic compound $(IV)$
$C.$ Alkaline chloroform solution is used to test primary amines $(II)$
$D.$ $2 KI + NaOCl + H _2 O \rightarrow NaCl + I _2+2 KOH$
Potassium iodide and sodium hypochlorite gives $\left( I _2+ KOH \right)$ which is used to test those compounds which have $image$ group (iodoform test). Hence the compound is $image$
$C{H_2} = C{H_2}\xrightarrow{{{O_2}/Ag}}X\xrightarrow{{473\,{\kern 1pt} K}}Y$