Aqua regia is a mixture of

Sulphur dioxide on reaction with chlorine in the presence of charcoal gives compound $(A)$. This on reaction with white phosphorus gives $SO_2$ and compound $(B)$. The correct statement about '$B$' is

Which of the following parent oxy acids does not have its hypo acid?

Identify $A, B, C$ and $D$ in the reactions:
$(I)$ $x Cl_2 + y NaOH \longrightarrow A + B + H_2 O_{(l)}$ (Cold,dil.)
$(II)$ $x Cl_2 + y NaOH \longrightarrow C + D + H_2 O_{(l)}$ (Hot,conc.)

$ClF_5$ at room temperature is a:

Which of the following sets represents the correct order of acidity?