\(B.\) 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 \(image\)
$(1)$ $\begin{matrix}
O \\
|| \\
{{C}_{6}}{{H}_{5}}-C-{{C}_{6}}{{H}_{5}} \\
\end{matrix}$
$(2)$ $C _{6} H _{5}- CHO$
$(3)$ $p - CH _{3}- C _{6} H _{4}- CHO$
$(4)$ $p - CH _{3} O - C _{6} H _{4}- CHO$