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

Which of the following compounds changes the color of an aqueous $FeCl_3$ solution?

$A$ colourless crystalline salt $X$ is soluble in dilute $HCl$. On adding $NaOH$ solution,it gives a white precipitate which is insoluble in excess of $NaOH$. $X$ is

Identify the correct reactions and observations from the following:
$(1) \ NH_4^+ \xrightarrow[K_2HgI_4]{KOH} \text{ Brown ppt. (Nessler's reagent)}$
$(2) \ Ni^{2+} \xrightarrow{dmg/OH^-} \text{ Rosy red ppt.}$
$(3) \ FeCl_3(aq.) \xrightarrow{NH_4OH} \text{ Reddish brown ppt.}$
$(4) \ CuSO_4(aq.) \xrightarrow{\text{excess } NH_4OH} \text{ Deep blue solution}$

Of the following sulphides,which one is insoluble in dilute acids but soluble in alkalies?

Match List-$I$ with List-$II$ and select the correct answer using the codes given below.

List-$I$ (Ion involved)	List-$II$ (Agent)
$(i) \, Ni^{2+}$	$(A).$ Sodium thiosulphate
$(ii) \, Ag^{+}$	$(B).$ Sodium nitroprusside
$(iii) \, Cu^{2+}$	$(C).$ Ammonia
$(iv) \, S^{2-}$	$(D).$ Dimethylglyoxime