The salt which responds to dilute and concentrated $H_2SO_4$ is

Choose the correct matching:-

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

Which of the following radicals does not liberate gas with ($Zn$ + dil. $HCl$) on warming?

$A$ salt gives violet vapours when treated with concentrated $H_2SO_4$,it contains

$M \text{ (Salt)} + \text{Dil. } HCl \xrightarrow{\text{Warm}} N \uparrow + P \downarrow$. Gas $N$ changes the colour of $FeSO_4$ solution into a yellow solution. Then,salt $M$ in the above reaction is:

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