Justify that glucose is an aldose form of sugar, with the help of a chemical reaction.

Glucose contains an aldehydic group ($-\text{CHO}$), as proven by its oxidation with a mild oxidizing agent such as bromine water ($\text{Br}_2 / \text{H}_2\text{O}$) to form gluconic acid (a six-carbon monocarboxylic acid), showing that the carbonyl group is an aldehyde: $\text{CHO}-(\text{CHOH})_4-\text{CH}_2\text{OH} + [\text{O}] \xrightarrow{\text{Br}_2 / \text{H}_2\text{O}} \text{COOH}-(\text{CHOH})_4-\text{CH}_2\text{OH}$