During the preparation of an ester, the "bridge" oxygen isfrom the:
Correct answer: A. Alcohol
- A. Alcohol
- B. Acid
- C. Alcohol or acid
- D. Catalyst
Explanation
Tracer studies using oxygen isotopes have shown that during Fischer esterification, the hydroxyl group (-OH) is lost from the carboxylic acid and the hydrogen atom is lost from the alcohol. This means the oxygen atom that links the two parts of the ester molecule (the "bridge" oxygen) comes from the alcohol.
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About Alcohols and Phenols
Alcohols are classified as primary, secondary or tertiary and studied through their hydrogen bonding, acidity, oxidation and reactions with active metals, acids and halogenating agents. Phenols require separate treatment because the hydroxyl group is attached to an aromatic ring, making their acidity and electrophilic substitution different from ordinary alcohols.
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