The laboratory test 'tailing of mercury' is used to identify:

Which of the following compounds does not liberate oxygen gas on warming with concentrated $H_2SO_4$?

Determine whether the following statements are True $(T)$ or False $(F)$:
$1.$ $SO_2$ is converted to $SO_3$ in the production of sulfuric acid.
$2.$ Ziegler catalyst is used for the oxidation of $SO_2$ to $SO_3$.

The bleaching action of $SO_2$ is due to its:

Which of the following elements shows polymorphism?

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