A chemical reaction in which two molecules are bonded together with the removal of a water molecule.

• A. Hydrolysis
• B. Compound
• C. Chemical Reaction
• D. Dehydration Synthesis

Answer: (D)

Dehydration synthesis is the process by which two molecules are joined to form a larger molecule while a water molecule is removed. In this reaction, one molecule donates a hydrogen and another donates a hydroxyl group, combining to form water and leaving behind a covalent bond that links the two units. This is how many biological polymers are built: for example, linking monosaccharides to form disaccharides, joining amino acids to make peptides and proteins, or forming triglycerides from glycerol and fatty acids. The essential idea is that bond formation is driven by the removal of water.

This differs from hydrolysis, which uses water to break bonds rather than form them. A compound is just any chemical substance, and a chemical reaction is a broad term for any change from reactants to products, not specific to the water-removal, bond-forming step described here.