Question

What are the hydrolysis products of

(i) Sucrose

(ii) What are the hydrolysis products of lactose?

Answer 1

(i) Sucrose is dextorrotatory but after hydrolysis produces dextrototatory glucose and laevorotatory fructose.
$C_{12}{H}_{22}{O}_{11}+H_{2}O\stackrel{Invertase}{\to }\underset{\beta -D-galaclose}{C_6{H}_{12}{O}_6}+\underset{D-(-)-fructose}{C_6{H}_{12}{O}_6}$
Since, the laevorotation of fructose $(-{92.4}^{\circ })$ is more than dextroration of clucose $(+{52.5}^{\circ })$ the mixture is laevoratatory and it is known as invert sugar.

(ii) Lactose on hydrolysis produce \beta - D - galactose and $\beta -D-glucose.$
$\underset{Lactose}{C_{12}{H}_{22}{O}_{11}+H_{2}O}\stackrel{Lactase}{\to }\underset{\beta -D-galactose}{C_6{H}_{12}{O}_6}+\underset{\beta -D-glucose}{C_6{H}_{12}{O}_6}$