How many of the following compounds will give a positive Iodoform test (yielding a yellow precipitat — Practical Organic Chemistry and Purification Chemistry Question
Question
How many of the following compounds will give a positive Iodoform test (yielding a yellow precipitate of $CHI_3$)? List: Ethanol, Methanol, Isopropyl alcohol, 2-Pentanone, 3-Pentanone, Acetaldehyde, Benzaldehyde, Acetophenone.
💡 Solution & Explanation
The iodoform test is given by compounds containing the acetyl group ($CH_3-CO-$) or the 1-hydroxyethyl group ($CH_3-CH(OH)-$). Ethanol ($CH_3CH_2OH$), Isopropyl alcohol ($CH_3-CH(OH)-CH_3$), 2-Pentanone ($CH_3-CO-CH_2CH_2CH_3$), Acetaldehyde ($CH_3-CO-H$), and Acetophenone ($C_6H_5-CO-CH_3$) give the test (5 compounds). Methanol, 3-Pentanone, and Benzaldehyde do not possess these groups and fail the test.