Question

What will happen when $D-(+)$-glucose is treated with methanolic —$HCl$ followed by Tollens’ reagent ?

• A. A black ppt. will be formed
• B. A red ppt. will be formed
• C. A green colour will appear
• D. No characteristic colour or ppt. will be formed.

Answer 1

Answer: (D)

Reaction of $D-(+)$-glucose with methanolic —$HCl$ leads to formation of methyl glucoside $(Cl—OH$ group is methylated) which, being acetal, is not hydrolysable by base, so it will not respond Tollens’ reagent.