Sodium nitroprusside,when added to an alkaline solution of sulphide ions,produces a purple colour due to the formation of:

Choose the correct matching $:-$

Column-$I$	Column-$II$
$P$. $NaBr + \text{Conc. } H_2SO_4 \rightarrow$	$A$. Colourless gas
$Q$. $Na_2S + \text{dil. } HCl \rightarrow$	$B$. Brown colour
$R$. $NaNO_2 + \text{dil. } HCl \rightarrow$	$C$. Rotten egg smell
$S$. $NaNO_3 + \text{Conc. } H_2SO_4 \rightarrow$	$D$. Paramagnetic

$A$ substance reacts with dilute $H_2SO_4$ to release a colorless gas,which turns baryta water $[Ba(OH)_2]$ turbid and decolorizes an acidic solution of dichromate. The presence of which of the following is indicated by this reaction?

Which of the following will not produce a precipitate with $AgNO_3$ solution?

Explain the brown ring test for nitrate ions.

An anion solution gives a white precipitate with $AgNO_3$ solution. The precipitate dissolves in dilute ammonia due to the formation of: