Question

Which from following tests decides the straight chain structure of glucose?

• A. Glucose forms oxime when treated with hydroxyl amine.
• B. Glucose forms cyanohydrin when treated with HCN.
• C. Glucose forms gluconic acid when treated with \(Br_2\) water.
• D. Glucose forms n-hexane when prolong heated with HI.

Hint:

Reduction of glucose with HI to n-hexane shows that all six carbons are in an unbranched chain.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept
The straight chain structure of glucose is established by its prolonged heating with HI, which reduces it completely.

Step 2: Reaction
\( \text{C}_6\text{H}_{12}\text{O}_6 \xrightarrow{\text{HI},\ \Delta} \text{n-hexane} \)

Step 3: Interpretation
Formation of n-hexane shows that the six carbon atoms are linked in a straight chain. The other tests show functional groups (CHO, OH), not the carbon chain.

Step 4: Compare the options
The answer is option (D).

Final Answer:
Formation of n-hexane with HI shows the straight chain. \[ \boxed{\text{(D) }\text{Glucose forms n-hexane when prolong heated with HI.}} \]