The $V^{-}A$ group precipitate was dissolved in $HNO_3$ and treated with an excess of $NH_4OH$. It gives a white precipitate because of:

To a solution of a substance,gradual addition of ammonium hydroxide results in a black precipitate which does not dissolve in excess of $NH_4OH$. However,when $HCl$ is added to the original solution,a white precipitate is formed. The solution contained

$A$ metal salt solution forms a yellow precipitate with potassium chromate in acetic acid,a white precipitate with dilute $H_2SO_4$,but gives no precipitate with $NaCl$. The metal salt solution will consist of:

When calomel reacts with a solution of $NH_4OH$,which compound is formed?

Match List-$I$ with List-$II$:

List-$I$ ($Test$/$reagent$)	List-$II$ ($Radical$ $identified$)
$A$. Lake Test	$I$. $NO_3^{-}$
$B$. Nessler's Reagent	$II$. $Fe^{3+}$
$C$. Potassium thiocyanate	$III$. $Al^{3+}$
$D$. Brown Ring Test	$IV$. $NH_4^{+}$

Choose the correct answer from the options given below:

Which compound is used to distinguish between $Fe^{2+}$ and $Fe^{3+}$ ions?