Why can concentrated sulfuric acid char sugar and paper?

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A labeled diagram highlights sulfur's position on the periodic table, showing its atomic number 16, symbol S, atomic weight range, electron configuration, and classification as a solid, strongly acidic, orthorhombic nonmetal at room temperature. — sulfur Chemical properties of sulfur.

Concentrated sulfuric acid is able to char materials like sugar and paper because it acts as a powerful dehydrating agent.

When the acid comes into contact with organic materials—such as carbohydrates like sugar or cellulose-based products like paper—it chemically withdraws the elements of water from the substance. By removing these components, the acid leaves behind a carbonaceous residue, which results in the characteristic burnt appearance of the material.12