$Silver \ nitrate$ $(AgNO_3)$ produces a black stain on the skin due to:

When fluoride is heated with conc. $H_2SO_4$ and $MnO_2$,the gas evolved is:

In the following reaction,identify the nature of the product formed by the complete hydrolysis of $BrF_5$ at $R.T.$:
$BrF_5 + 3H_2O \longrightarrow HBrO_3 + 5HF$

Which is the most volatile compound?

Consider the following reactions :
$(i)$ $F_2 + 2X^{-} \to 2F^{-} + X_2$ $(X = Cl, Br, I)$
$(ii)$ $Cl_2 + 2X^{-} \to 2Cl^{-} + X_2$ $(X = Br, I)$
$(iii)$ $I_2 + 2Br^{-} \to 2I^{-} + Br_2$
Which option has only the correct set of reactions?

Elements of which group form anions most readily?