Anhydride of sulphuric acid is

Compound 'X' is the anhydride of sulphuric acid, the hybridisation of central atom in a molecule of 'X' is

Anhydride of nitric acid is_____and anhydride of phosphoric acid is________.

Anhydride of pyrosulphuric acid is

The anhydride of pyrosulphuric acid is

Which are the anhydrides of sulphurous acid and sulphuric acid ?