Question

What happens to glucose or galactose when the cu2+ in benedict's reagent is reduced?

Answer 1

Answer is: glucose or galactose give up an electron and they are oxidized, usually to acid.
Benedict's reagent is a mixture of sodium citrate, sodium carbonate (Na₂CO₃) and copper(II) sulfate (CuSO₄).
When Benedict's reagent is mixed and heated with glucose and galactos, the copper accept the electrons and become reduced. Benedict's test detects the presence of aldehydes in solution.

Answer 2

Gluconic acid is formed when Benedict's reagent is reduced by glucose or galactose.

Step-by-step explanation:

Benedict's reagent: Alkaline solution of copper sulfate , sodium citrate and sodium carbonate

Glucose and galactose both are reducing sugar. Both of them reduces copper(II) ion in Benedict's reagent into copper (I) ion.

During this reaction glucose or galactose gets converted into gluconic acid and red precipitate of copper (I) oxide is obtained along with formation of water.

`CHO-(CHOH)_4-CH_2OH+Cu^(2+)\rightarrow ^-OOC-(CHOH)_4-CH_2OH+H_2O+Cu_2O`