Concentrated $H_2SO_4$ reacts with $PCl_5$ to produce

When $PbO_2$ reacts with concentrated $HNO_3$,the gas evolved is

Given below are two statements:
Statement $I$: Oxygen being the first member of group $16$ exhibits only $-2$ oxidation state.
Statement $II$: Down the group $16$ stability of $+4$ oxidation state decreases and $+6$ oxidation state increases.
In the light of the above statements,choose the most appropriate answer from the options given below:

Although oxygen is more electronegative than sulfur,$H_2S$ is acidic while $H_2O$ is neutral. This is because ..........

When $SO_2$ is passed through cupric chloride $(CuCl_2)$ solution,what is the observation?

What is the atomicity of sulfur in rhombic sulfur?