Which of the following halogens does not form oxoacids?

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

Chlorine water on standing loses its colour and forms:

Choose the $CORRECT$ reason for fluorine being a stronger oxidising agent than chlorine.
$I$. Low enthalpy of dissociation of $F-F$ bond
$II$. High hydration enthalpy of $F^-$
$III$. Low atomisation enthalpy of $F_2$

The least number of oxyacids are formed by

Chlorine reacts with sodium hydroxide under various conditions to give: