Question

Explain charring (action of concentrated H2S04 on carbohydrate/sugar).

Answer 1

Sulphuric acid being a dehydrating agent removes water from sugar as carbohydrates. Carbon left behind is sugar- charcoal and the process is called charring.

$$\underset{(\mathrm{Sugar}\mathrm{i}\cdot \mathrm{e}\cdot \mathrm{sucrose})}{\mathrm{C}{\phantom{A}}_{12}\mathrm{H}{\phantom{A}}_{22}\mathrm{O}{\phantom{A}}_{11}}+\underset{(\mathrm{cone}\cdot )}{\mathrm{H}{\phantom{A}}_2\mathrm{SO}{\phantom{A}}_4}\stackrel{\mathrm{Charring}}{\to }\underset{(\mathrm{Sugar}\mathrm{charcoal})}{12\mathrm{C}\downarrow +}11\mathrm{H}{\phantom{A}}_2\mathrm{O}$$