In which of the following compounds will nitrogen not be detected by the Lassaigne test?

$A$ solution of $m-$chloroaniline,$m-$chlorophenol and $m-$chlorobenzoic acid in ethyl acetate was extracted initially with a saturated solution of $NaHCO_3$ to give fraction $A$. The left over organic phase was extracted with dilute $NaOH$ solution to give fraction $B$. The final organic layer was labelled as fraction $C$. Fractions $A$,$B$ and $C$ contain respectively

In the detection of carbon and hydrogen,the organic compound is heated with which of the following?

Identify the binary mixture$(s)$ that can be separated into individual compounds by differential extraction,as shown in the given scheme.
$(A)$ $C_6H_5OH$ and $C_6H_5COOH$
$(B)$ $C_6H_5COOH$ and $C_6H_5CH_2OH$
$(C)$ $C_6H_5CH_2OH$ and $C_6H_5OH$
$(D)$ $C_6H_5CH_2OH$ and $C_6H_5CH_2COOH$

During the fusion of an organic compound with sodium metal,the nitrogen present in the organic compound is converted into:

The Lassaigne's extract is boiled with dilute $HNO_3$ before testing for halogens because,