Glucose is a strong reducing agent. It is oxidized to gluconic acid by
(a) `Br_(2)//H_(2)O`
(b) Fehling's solution
(c ) Tollen's reagent
(d) Benedict's solution

Options

A. b,c
B. b,c,d
C. a,b,c
D. a,b,c,d

Answer

D

Explanation

They are all mild oxidisizing agents, thus only the aldehyde group oxidized.
`HOCH_(2) (CHOH)_(4) overset([O])rarr HOCH_(2) underset("Gluconic acid")(CHOH)_(4) CO_(4) H`
Benedict's solution is an alkaline solution of cupric ions complexed with citrate ion. During reduction the deep-blue colour of the Fehling's solution (or Benedict's solution) is discharged, and red cuprous oxide precipitates.
`F.S, B.S` and `T.R` cannot be used to differentiate aldeoses from ketoses (`alpha`- hydroxyetones) because ketoses also reduce these reagents. Also, oxidations by these reagents can't be used for the preparation of aldonic acids (monocarboxylic acids) from aldoses as they are alkaline reagents and therefore can use extensive isomerization and event decomposition of the chain.
Bromine water, bein an acidic reagent, does not cause isomerization of the molecule. Therefore, it oxidizes aldoses, but not ketose, and (b) to synthesize the aldonic acid from an aldose. During the reaction, there is loss of the orange colour of the aqueous `Br_(2)` solution.