Which anion's aqueous solution gives a white precipitate with $AgNO_3$,which is soluble in excess $NH_4OH$?

Which ion's salt solution produces a violet layer when chlorine water and chloroform are added?

$A$ chloride salt solution acidified with dil. $HNO_3$ gives a curdy white precipitate,$[A]$,on addition of $AgNO_3$. $[A]$ on treatment with $NH_4OH$ gives a clear solution,$B$. Identify $[A]$ and $B$.

Explain the brown ring test for nitrate ions.

Which salt produces a white precipitate with $AgNO_3$ solution,which becomes black on standing?

An unknown salt (anion) reacts with dilute $HCl$ to produce gas $X$ (rotten egg smell). Choose the incorrect option regarding gas $X$.