Select the correct match for the separation of anions using the given reagent.

In the qualitative analysis of nitrate,a brown ring is formed due to the formation of:

$[X] +$ dil. $H_{2}SO_{4} \longrightarrow [Y]:$
Colourless,suffocating gas
$[Y] + K_{2}Cr_{2}O_{7} + H_{2}SO_{4} \longrightarrow$
Green colouration of solution
Then,$[X]$ and $[Y]$ are

$P_{(Coloured \ Solution)} + BaCl_2 \to Q \downarrow_{(White)} + R_{(Coloured \ Solution)}$
Then salt $P$ in above reaction is

Neutral ferric chloride is added to the aqueous solution of acetate. $A$ blood-red colour is obtained; this is due to the formation of which compound?

Sodium salt solution $+ \, AgNO_3$ solution $\to$ Coloured precipitate: If the coloured precipitate is soluble in both dilute $HNO_3$ and excess concentrated $NH_3$ solution,then which of the following anions is present in the salt solution?