When $Cl_2$ water is added to a salt solution containing chloroform,the chloroform layer turns violet. The salt contains:

In the test of sulphate radical,the white precipitate of sulphate is soluble in

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

When $Y$ is treated with $KMnO_4$,then the final precipitate is of:
$'X' \xrightarrow[BaCl_{2} \text{ solution}]{} 'Y' \quad (\text{White ppt., insoluble in dil. } HCl)$
$'X' \xrightarrow[\text{Flame test}]{} \text{Golden yellow flame}$

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

To an inorganic mixture,dilute $H_2SO_4$ is added in the cold; a colourless,odourless gas is evolved. The mixture contains: