Question

Cone H₂SO₄ acts as a ‘drying agent’ & a ‘dehydrating agent’. Explain and differentiate the words in italics.

Answer 1

Cone H₂SO₄ when acts as a drying agent, absorbs only moisture from the substance and makes it dry without changing its composition.
When cone. H₂SO₄ acts as a dehydrating agent, it removes water molecules from the composition of substance and reacts chemically, produces a new substance with new properties.

e.g.   \[\ce{\underset{\text{Ethyl alcohol}}{C2H5OH}->[conc. H2SO4]\underset{\text{ethylene}}{C2H4} + H2O}\]

\[\ce{\underset{\text{formic acid}}{HCOOH} + ->[conc. H2SO4]\underset{\text{carbon monoxide}}{CO} + H2O}\]