In which of the following reactions is $SO_2$ gas not produced?

The correct order of $K_a$ in aqueous solution at $298 \ K$.

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 $H_2S < H_2Se < H_2Te$.

Given below are two statements: Statement $I$: The covalency of oxygen is generally two but it can exceed up to four. The oxidation state of oxygen in $SO_2$ is $-2$ and in $OF_2$ it is $+2$. Statement $II$: The anomalous behaviour of oxygen when compared to the other elements of group $16$ is due to its small size and high electronegativity. In the light of the above statements, choose the correct answer from the options given below.

In which of the following is the formation of polyanions maximum?

What are the specific densities of $\alpha$-sulphur and $\beta$-sulphur?