In Lassaigne's extract of an organic compound,both nitrogen and sulphur are present,which gives blood red colour with $Fe^{3+}$ due to the formation of-

During the halogen test,the sodium fusion extract is boiled with concentrated $HNO_3$ to ... .

Match the organic compounds in column $I$ with the Lassaigne's test results in column $II$ appropriately.

Column $I$	Column $II$
$A$. Aniline	$i$. Red colour with $FeCl_3$
$B$. Benzene sulfonic acid	$ii$. Violet colour with sodium nitroprusside
$C$. Thiourea	$iii$. Blue colour with hot and acidic solution of $FeSO_4$

Which of the following compounds will give a positive Lassaigne's test for both nitrogen and halogen?

The volume of nitrogen is measured by which apparatus in the Dumas method?

$A$ 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