Which process is used for the manufacture of $H_2SO_4$?

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

Which of the following is the most basic oxide?

Which of the following substances gives oxygen upon moderate heating?

Which of the following acids is the strongest?

Given below are two statements:
Statement $I$: The boiling point of hydrides of Group $16$ elements follows the order
$H_2O > H_2Te > H_2Se > H_2S$.
Statement $II$: On the basis of molecular mass,$H_2O$ is expected to have a lower boiling point than the other members of the group,but due to the presence of extensive $H$-bonding in $H_2O$,it has a higher boiling point.
In the light of the above statements,choose the correct answer from the options given below: