Question

Explain the hydrolysis of sucrose.

Answer 1

1. Sucrose (Cl₁₂H₂₂O₁₁) is dextrorotatory (+ 66.5).
2. On hydrolysis with dilute acid or an enzyme called invertase, sucrose gives an equimolar mixture of D - (+) glucose and D - (-) fructose.
   \[\ce{\underset{(Sucrose)}{Cl12H22O11} + H2O ->[H+][or invertase]\underset{D - (+) glucose}{C6H12O6} + \underset{D - (-) fructose}{C6H12O6}}\]
3. Since the laevorotation of fructose (- 92.4°) is larger than the dextrorotation of glucose (+ 52.7°), the hydrolysis product has net laevorotation.
4. Hence hydrolysis of sucrose is also called inversion of sucrose, and the product is called invert sugar.