Lead sulphate is soluble in:

Which of the following reagents is used to detect the presence of $Fe^{3+}$ ions in a solution?

Assign $A$,$B$,$C$,$D$ from the given type of reaction: $NiCl_2 (aq) + NaNO_3 (aq) \longrightarrow$ No reaction.

Statement-$1$: Few drops of $HNO_3$ are added before proceeding to $III^{rd}$ group.
Statement-$2$: For the oxidation of $Fe^{+2} \rightarrow Fe^{+3}$.

Consider the following reactions:
$X(aq.) \xrightarrow{K_4[Fe(CN)_6]}$ Chocolate brown ppt.
$X(aq.) \xrightarrow{AgNO_3}$ White ppt. (insoluble in dil. $HNO_3$)
Then $X$ will be:

The group reagent $NH_4Cl_{(s)}$ and aqueous $NH_3$ will precipitate which of the following ions?