When $H_2S$ gas is passed through a solution,it reacts to form a white precipitate. Which ion is present in the solution?

The solution of $BiCl_{3}$ in dil. $HCl$ when diluted with water,forms a white precipitate which is:

$Al^{3+}$,$Fe^{3+}$,$Zn^{2+}$,and $Ni^{2+}$ ions are present in an acidic solution. Excess of ammonium chloride $(NH_4Cl)$ solution is added followed by the addition of ammonium hydroxide $(NH_4OH)$ solution. The resulting precipitate will contain:

$A$ (Orange color compound) $\xrightarrow{(B) + \text{conc. } H_2SO_4}$ $C$ (Red gas) $\xrightarrow{NaOH + AgNO_3}$ $D$ (Red ppt.) $\xrightarrow{\text{NH}_3 \text{ solution}}$ Yellow solution.
$B$ $\xrightarrow[\Delta]{NaOH}$ $F \uparrow$ (Gives white fumes with $HCl$).
Identify $B$ and $F$ respectively :-

Assign $A$,$B$,$C$,$D$ from the given type of reaction.
$(NH_4)_2SO_4 + Sr(OH)_2 \longrightarrow SrSO_4 \downarrow + 2NH_3 \uparrow + 2H_2O$

Given below are certain cations. Using inorganic qualitative analysis,arrange them in increasing group number from $0$ to $VI$.
$A. Al^{3+}$ $B. Cu^{2+}$
$C. Ba^{2+}$ $D. Co^{2+}$
$E. Mg^{2+}$
Choose the correct answer from the options given below: