Question

Glucose on prolonged heating with $HI$ gives :

• A. n-Hexane
• B. 1-Hexene
• C. Hexanoic acid
• D. 6-iodohexanal

Answer 1

The Correct Option is A

To determine the product formed when glucose is heated with hydrogen iodide ($HI$), we must consider the chemical reaction process and the nature of glucose.

Glucose is a monosaccharide with the molecular formula C_6H_{12}O_6. When glucose is subjected to prolonged heating with $HI$, it undergoes a reduction reaction. In this process, $HI$ acts as a reducing agent, converting the glucose into a simpler alkane, specifically $n$-hexane.

1. Glucose is reduced to remove its hydroxyl groups and oxygen atoms, leading to the formation of an alkane.
2. The reaction proceeds through successive removal of functional groups until a saturated hydrocarbon chain is formed.
3. The resulting compound, n-hexane, is a straight-chain alkane with the formula C_6H_{14}.

The reduction of glucose with $HI$ is a classic laboratory reaction demonstrating the ability of hydrogen iodide to reduce organic compounds by fully substituting oxygen atoms with hydrogen atoms, in this case forming a saturated hydrocarbon.

Conclusion: The correct answer is n-Hexane. Thus, the prolonged heating of glucose with $HI$ yields n-hexane.

Other options:

• 1-Hexene: A possible compound from dehydration reactions but not formed in this reduction process.
• Hexanoic acid: An entirely different functional group product requiring oxidation rather than reduction.
• 6-iodohexanal: Would require selective iodination rather than complete reduction to an alkane.