Which one of the following alcohol is indicated by formation of yellow crystals in Iodoform test?
Correct answer: B. Ethanol
- A. Methanol
- B. Ethanol
- C. Butanol
- D. Propanol
Explanation
Only secondary alcohols with a methyl group on the carbon atom adjacent to the hydroxyl group give a positive iodoform test. This is because the iodoform test involves the oxidation of the methyl group to a carbonyl group, which then reacts with iodine and sodium hydroxide to form a yellow precipitate of iodoform.
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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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