Discussion Forum

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)

Answer:

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

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