Aqueous solution of which of the following cation gives a precipitate with potash alum?

The only cations present in a slightly acidic solution are $Fe^{3+}$,$Zn^{2+}$,and $Cu^{2+}$. The reagent that when added in excess to this solution would identify and separate $Fe^{3+}$ in one step is

In the analysis of basic radicals,the group reagent $H_2S$ gas is generally used in which groups?

The pair$(s)$ of ions where $BOTH$ the ions are precipitated upon passing $H_2S$ gas in the presence of dilute $HCl$,is(are):
$(A) Ba^{2+}, Zn^{2+}$
$(B) Bi^{3+}, Fe^{3+}$
$(C) Cu^{2+}, Pb^{2+}$
$(D) Hg^{2+}, Bi^{3+}$

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	$(d)$ $Na_2[Fe(CN)_5NO]$

When a salt is treated with sodium hydroxide solution,it gives gas $X$. On passing gas $X$ through reagent $Y$,a brown-coloured precipitate is formed. $X$ and $Y$ respectively,are