The copper wire test for halogens is known as:

Given below are two statements :
Statement $I :$ In Lassaigne's test,the covalent organic molecules are transformed into ionic compounds.
Statement $II :$ The sodium fusion extract of an organic compound having $N$ and $S$ gives prussian blue colour with $FeSO_4$ and $FeCl_3$.
In the light of the above statements,choose the correct answer from the options given below.

During the detection of phosphorus in an organic compound,a yellow precipitate is formed due to the formation of:

In $Kjeldahl’s$ method,$CuSO_4$ acts as

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

Which compound is formed as a violet-colored complex during the test for sulfur?