Question

Give an equation of CaO preferred over Sulphuric acid as a drying agent?

Answer 1

Explanation:

Calcium oxide would be preferred over sulfuric acid when trying to dry basic compounds (ammonia or amines, for example), since those would react with the acid. It’s also probably a better choice for alcohols or many other organic molecules that would be attacked by H2SO4.

For many other cases, sulfuric acid would be preferred, either because whatever you’re trying to dry is an acid (which would react with CaO) or just because it’s conveniently liquid.