The charring of sugar (for example, when treated with concentrated sulphuric acid or upon strong heating) is primarily due to:

Step-by-step solution

Concentrated sulphuric acid is a strong dehydrating agent. When sugar (sucrose, C₁₂H₂₂O₁₁ ) is treated with concentrated H₂SO₄ , the acid removes water molecules from the sugar molecules. The chemical reaction is: C₁₂H₂₂O₁₁ conc. H₂SO₄ 12C + 11H₂O This process leaves behind elemental carbon, which appears as a black spongy mass, causing the charring effect. This removal of water is known as dehydration. Answer: dehydration