Which of the following can be used instead of $NH_4Cl$ in the analysis of group $III$ radicals?

When $H_2S$ is passed through a solution in $Group-II$ analysis,it sometimes becomes milky. This indicates the presence of:

Which reagent is used in the qualitative analysis of Group $IV$ cations?

On passing $H_2S$ gas,a black precipitate of $II$ group is obtained. The mixture may not contain:

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

Column-$I$	Column-$II$
$(i)$ Blood like red colour	$(a)$ $Fe_4[Fe(CN)_6]_3$
$(ii)$ Sodium nitroprusside	$(b)$ $(NH_4)_2MoO_4$
$(iii)$ Ammonium molybdate	$(c)$ $[Fe(SCN)]^{2+}$
$(iv)$ Ferri-ferro cyanide	$(d)$ $Na_2[Fe(CN)_5NO]$

$M^{n+}(aq.) + KI \to X\downarrow \text{ (ppt.)}$ $\xrightarrow{Excess KI} \text{ppt. remains insoluble in excess } KI \text{ solution. Then cation } M^{n+}(aq.) \text{ can be}$