Which functional group is most commonly involved in a dehydration reaction during the formation of an ether or an ester?

• A. Hydroxyl group ($-\mathrm{OH}$)
• B. Carboxyl group ($-\mathrm{COOH}$)
• C. Amino group ($-\mathrm{NH}{2}_{}$)
• D. Carbonyl group ($C=O$)

Answer: (A)

Verified step by step guidance

1. Identify the functional groups involved in the formation of ethers and esters. Ethers are typically formed by the reaction of two alcohols, while esters are formed by the reaction of an alcohol and a carboxylic acid.
2. Understand that a dehydration reaction involves the removal of a water molecule (\(H_2O\)) during the formation of a new bond between two molecules.
3. Recognize that the hydroxyl group (\(-OH\)) is the key functional group that loses a hydrogen atom during dehydration, allowing the formation of an ether or ester linkage.
4. For ester formation, the hydroxyl group from the alcohol and the hydroxyl part of the carboxyl group (\(-COOH\)) combine, releasing water and forming the ester bond (\(-COO-\)).
5. For ether formation, two hydroxyl groups from two alcohol molecules lose water and form an ether linkage (\(-O-\)) between the two carbon chains.