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:

Which one of the following is the correct decreasing order of boiling point?

Which of the following statements is $NOT$ correct about ozone?

What happens when:
$(i)$ Concentrated $H_2SO_4$ is added to calcium fluoride
$(ii)$ $SO_3$ is passed through water?

Which of the following has the maximum tendency to form polyanions?

Identify the correct statements from the following.
$(i)$ Oxygen shows $-2, -1, +1$ and $+2$ oxidation states.
$(ii)$ The thermal stability of $H_2O, H_2S$ and $H_2Se$ follows the order $H_2O < H_2S < H_2Se$.
$(iii)$ The reducing nature of $H_2S, H_2Se$ and $H_2Te$ follows the order $H_2S < H_2Se < H_2Te$.