Photoconductors in xerox machines use which of the following?

What is the product formed when $SO_2$ reacts with an aqueous solution of sodium hydroxide?

The incorrect statement$(s)$ about $O_3$ is (are):

When an inorganic compound reacts with $SO_2$ in an aqueous medium,it produces $(A)$. $(A)$ on reaction with $Na_2CO_3$ gives compound $(B)$,which with sulphur,gives a substance $(C)$ used in photography. Compound $(C)$ is:

Identify the correct formula of oleum from the following.

Identify the incorrect statement regarding ozone $(O_3)$.