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)

No characteristic colour or ppt. will be formed.

Answer 2

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.