A compound that could be dried by using conc. tetraoxosulphate (VI) acid and not by calcium oxide is likely to be

A.

a deliquescent salt

B.

a neutral salt

C.

an alkaline gas

D.

an acid anhydride

Correct answer is D

The compound that could be dried by using conc. tetraoxosulphate (VI) acid and not calcium oxide is an acid anhydride.
Acid anhydrides are compounds that can react with water to form acids. When acid anhydrides are exposed to air, they will absorb water from the air and become hydrated. This can make them difficult to dry with calcium oxide, which is a base.