In Kjeldahl's method of estimation of $N$,$CuSO_4$ acts as

Consider the following table$-$

Column-$I$	Column-$II$
$A$. Best and latest technique for isolation,purification and separation of organic compounds	$i$. Chromatography
$B$. In Lassaigne's test for $N$	$ii$. Vacuum distillation
$C$. In Lassaigne's test for $S$	$iii$. Violet coloured complex is formed
$D$. Aniline is separated from water by	$iv$. Prussian blue coloured complex is formed
$E$. Glycerol is purified from spent lye	$v$. Steam distillation

The correct match is$-$

When sodium fusion extract of an organic compound is boiled with iron$(II)$ sulphate solution followed by addition of concentrated $H_2SO_4$,it gives a Prussian blue colour. This confirms the presence of which element?

Explain the reason for the fusion of an organic compound with metallic sodium for testing nitrogen,sulphur,and halogens.

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

Match column $-I$ and column $-II$ with the correct relation:

Column $-I$	Column $-II$
$(i).$ Prussian blue	$(a).$ Presence of phosphorus
$(ii).$ Yellow precipitate	$(b).$ Presence of sulphur
$(iii).$ Purple solution	$(c).$ Presence of nitrogen
$(iv).$ Black precipitate	$(d).$ Presence of chlorine