The qualitative distinction of $ZnSO_4$ and $Al_2(SO_4)_3$ can be done by using the reagent

Which ion is not precipitated by both $HCl$ and $H_2S$?

$(T)$ imparts violet colour $\xrightarrow{compd.\,(U) + conc.\,H_2SO_4}$ $(V)$ Red gas $\xrightarrow{NaOH + AgNO_3}$ $(W)$ Red ppt. $\xrightarrow{NH_3\,soln.}$ $(X)$
$(W)$ Red ppt. $\xrightarrow{dil.\,HCl}$ $(Y)$ white ppt.
$(U)$ $\xrightarrow[\Delta]{NaOH}$ $(Z)$ gas (gives white fumes with $HCl$)?
$(T)$ sublimes on heating
Identify $(T)$ to $(Z).$

The colour of copper sulphide is

Among the following cations,the number of cations which will give characteristic precipitate in their identification tests with $K_4[Fe(CN)_6]$ is :
$Cu^{2+}, Fe^{3+}, Ba^{2+}, Ca^{2+}, NH_4^{+}, Mg^{2+}, Zn^{2+}$

Which of the following basic radicals will not be precipitated by $H_2S$ gas in the presence of $NH_3$?