Q20 / 125 · BITSAT 2016 · Chemistry

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
  • Correct answer
    D
    No characteristic colour or ppt. will be formed.

Solution

Reaction of $\mathrm{D}-(+)$ -glucose with methanolic $-\mathrm{HCl}$ leads to formation of methyl glucoside $\left(\mathrm{C}_{1}-\mathrm{OH}\right.$ group is methylated) which, being acetal, is not hydrolysable by base, so it will not respond Tollens'reagent.

Hence, the correct answer is option: 'D'.

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