Fructose reduces Tollen's reagent due to:enolisation of fructose followed by conversion to glucose (having aldehydic group) by the base present in Tollen's reagentasymmetric carbonsprimary alcoholic groupsecondary alcoholic group

Fructose reduces Tollen's reagent due to the process of enolisation. Here's a step-by-step explanation:

1. Enolisation: Fructose, a ketohexose, undergoes enolisation, which is the process of forming an enol (a compound with a hydroxyl group attached to a carbon that is double-bonded to another carbon).

2. Conversion to Glucose: The base present in Tollen's reagent then converts the enolised fructose into glucose. This is possible because fructose and glucose are isomers, meaning they have the same molecular formula but different structural formulas.

3. Presence of Aldehydic Group: Glucose has an aldehydic group (a carbonyl group at the end of the carbon chain), which can reduce Tollen's reagent. This is because Tollen's reagent, which contains silver ions, is a mild oxidising agent that can oxidise aldehydes but not ketones.

4. Oxidation-Reduction Reaction: The aldehydic group in glucose is oxidised to a carboxylic acid, while the silver ions in Tollen's reagent are reduced to metallic silver. This is why Tollen's reagent is used to test for the presence of reducing sugars like glucose.

So, the reduction of Tollen's reagent by fructose is due to the enolisation of fructose and its subsequent conversion to glucose by the base in Tollen's reagent. The primary and secondary alcoholic groups in fructose do not directly contribute to the reduction of Tollen's reagent.