Question

Hydrolysis of sucrose is called
A. Mutarotation
B. Saponification
C. Inversion
D. De-esterification

Answer 1

Hint: When sucrose is treated with water, it is hydrolysed to give two monomeric units where the hydrolysis brings about a change in the sign of rotation i.e. the sign of the reactant is different when compared to the sign of the products formed. So, you should know what this change is called?


Complete step by step solution:
Hydrolysis of sucrose is often referred to as the inversion and the resulting sugar formed on hydrolysis is called as invert sugar. The reason for this name is found in the effect of invert sugar upon a beam of light.
So, let’s see what happens when a beam of light is allowed to pass through sucrose solution.
So, if a straight beam of light is allowed to pass through a solution of sucrose in an instrument called polariscope, the beam of light is rotated to the right and thus, the sucrose is called “dextro-rotatory”.
But, after the sucrose is hydrolysed, the ray of light is rotated to the left and now it is called “laevo-rotatory”. Because of this inversion of a beam light, hydrolysed sucrose is called as invert sugar and the process is called as “inversion”.
${{C}_{12}}{{H}_{22}}{{O}_{11}}+{{H}_{2}}O\xrightarrow{HCl}{{C}_{6}}{{H}_{12}}{{O}_{6}}+{{C}_{6}}{{H}_{12}}{{O}_{6}}$
 Sucrose Glucose Fructose
Thus, the process is called inversion.

Hence, the correct option will be C.


Note: Sucrose is dextro-rotatory with a specific rotation $+{{66.5}^{o}}$.On hydrolysis in presence of hydrochloric acid or enzyme invertase, it gives equimolar mixture of glucose with specific rotation $+{{52.7}^{o}}$and fructose with a specific rotation $+{{92.4}^{o}}$. Since, the specific rotation of glucose is less than that of fructose, the resulting solution after hydrolysis becomes laevorotatory (in short there is change in the optical sign).