Discussion Forum



1)

For ' invert sugar ',  the correct statement(s) is (are)

( Given: specific rotations of (+) - sucrose,(+)- maltose, L-(-)-glucose and L-(+)-fructose in aqueous solution are +66°, +140°, -52° and 92° , respectively)


A) Invert sugar is prepared by acid catalysed hydrolysis of maltose

B) Invert sugar is an equimolar mixture of D-(+) -glucose and D-(-)-fructose

C) Specific rotation of invert sugar is $-20^{0}$

D) On reaction with$Br_{2}$ water, invert sugar forms saccharic acid as one of the products

Answer:

Option B,C

Explanation:

If there is inversion of specific rotation from (+) to (-), then invert sugar is formed.

(a) $C_{12}H_{22}O_{11}[(+)maltose140^{0}]+H_{2}O\rightarrow Glucose [D(+) 52^{0}]$

(b) $ C_{12}H_{22}O_{11}[(+)sucrose+66^{0}]+H_{2}O$

                                                 $\rightarrow Glucose [D(+) 52^{0}]+Fructose [L(-)-92^{0}] $

                                                                                                   -40° for 2 moles mixture

                                                                                                    -20° for 1 mole mixture

 There is formation of invert sugar, Thus, correct

(c) Specific rotation of invert sugar is -20° per mole. Thus, correct

(d) $Br_{2} $ water is a weak oxidising agent. 

           It oxidises -CHO to -COOH.

  $- CH_{2} OH$ group is not affected

1422021422_c10.JPG

 $HNO_{3}$ (a strong oxidising agent) oxidises invert sugar to saccharic acid. Thus, incorrect