Methyl D-glucoside on reaction with HIO ₄ consumes two moles of the reagent and produces one mole of HCOOH and a dialdehyde (A) having the following structure: This result proves that glucose has:

Step-by-step solution

Methyl D-glucoside is an acetal of glucose. The reaction with periodic acid ( HIO₄ ) cleaves the carbon-carbon bonds of vicinal diols. Let us analyze the cleavage for a six-membered (pyranose) ring structure: In methyl D-glucopyranoside, the ring is formed between C1 and C5. The hydroxyl groups at C2, C3, and C4 are adjacent to each other, forming a continuous sequence of three secondary alcohol groups: - CH(OH) - CH(OH) - CH(OH) - . HIO₄ will cleave the bonds between C2-C3 and C3-C4. This requires exactly 2 moles