When monosaccharides form cyclic hemiacetals, which type of molecule is released during the linkage process?

• A. Carbon dioxide
• B. $H_{2}O$
• C. Methane
• D. O2

Answer: (B)

Verified step by step guidance

1. Understand that monosaccharides can form cyclic structures through a reaction between the hydroxyl group and the carbonyl group within the same molecule, resulting in a hemiacetal formation.
2. Recognize that during the formation of a cyclic hemiacetal, a new bond is formed between the carbonyl carbon and the oxygen of the hydroxyl group, creating a ring structure.
3. Identify that this process involves the removal of a small molecule as a byproduct of the reaction.
4. Recall that in organic chemistry, the formation of acetals and hemiacetals typically involves the release of a water molecule (H₂O) as the hydroxyl group (OH) and a hydrogen atom (H) from the carbonyl group combine.
5. Conclude that the molecule released during the formation of cyclic hemiacetals from monosaccharides is water (H₂O), as it is a common byproduct in such condensation reactions.