Which of the following halides react$(s)$ with $AgNO_{3(aq)}$ to give a precipitate that dissolves in $Na_2S_2O_{3(aq)}$?
$A$. $HCl$
$B$. $HF$
$C$. $HBr$
$D$. $HI$

Which reagent below would enable you to remove sulphate ions from a solution containing both sulphate and chloride ions?

In a test tube containing a salt, a few drops of dilute $\text{H}_2\text{SO}_4$ were added, which gave colourless vapours having the smell of vinegar. The vapours turned the blue litmus paper red. Identify the correct anion from the following:

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

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

List-$I$ (Anion)	List-$II$ (Gas evolved on reaction with dil. $H_2SO_4$)
$A. CO_3^{2-}$	$I$. Colourless gas which turns lead acetate paper black
$B. S^{2-}$	$II$. Colourless gas which turns acidified potassium dichromate solution green
$C. SO_3^{2-}$	$III$. Brown fumes which turn acidified $KI$ solution containing starch blue
$D. NO_2^{-}$	$IV$. Colourless gas evolved with brisk effervescence,which turns lime water milky

Choose the correct answer from the options given below:

The brown ring test is used to detect the presence of which ion?