Which substance is used as a gaseous insulator in high-voltage generators?

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

What are the products formed when chlorine is passed through an aqueous hypo solution?

What is the product formed when concentrated $HNO_3$ reacts with iodine?

Which of the following compounds is $NOT$ in the gaseous phase at $25^{\circ} C$?

The correct order of bond dissociation enthalpy of halogens is: