Answer:
aldonic acid, Barfoed's reagent is copper(II) acetate in acetic acid.
Step-by-step explanation:
Barfoed's test is the chemical test which is used for the detection of the presence of the monosaccharides.
The aldehyde group of aldose sugar is oxidized to the carboxylic group known as, aldonic acid.
RCHO + 2Cu²⁺ + 2H₂O → RCOOH + Cu₂O↓ + 4H⁺
Barfoed's reagent is copper(II) acetate in acetic acid which on reduces to copper(I) oxide forming a brick-red precipitate.