What will happen when $\mathrm{D}-(+)$ -glucose is treated with methanolic $-\mathrm{HCl}$ followed by Tollens' reagent?

Question

Aicharya · Accepted Answer

When $\mathrm{D}-(+)$ - glucose is treated with methanolic $-\mathrm{HCl}$ followed by Tollens' reagent, no characteristic colour or ppt. will be formed.
Reaction of $\mathrm{D}-(+)$ glucose with methanolic $-\mathrm{HCl}$ leads to formation of methyl glucoside
(-OH group at $\mathrm{C}_{1}$ of hemiacetal is methylated to form acetal). Acetal, is not hydrolysable by base, so it will not respond Tollen's reagent.
Note: Tollen's reagent oxidises aldehyde to carboxylate group. Tollen's reagent itself is reduced to black silver mirror. If aldehdye group is not free (such as converted to acetal), this reaction will not occur. ,

What will happen when $\mathrm{D}-(+)$ -glucose is treated with methanolic $-\mathrm{HCl}$ followed by…

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