Nine compounds are separately warmed with $I X_{2}$ / $NaOH$ : ethanol, propan-2-ol, phenyl methyl ketone, benzaldehyde, pentan-3-one, ethanal, propanal, methanol and butan-2-one. How many give a positive iodoform test?

Answer: C

Positive: ethanol, propan-2-ol (both oxidised to

CH X_{3} CO X^{-}

compounds), phenyl methyl ketone, ethanal and butan-2-one. Negative: benzaldehyde, pentan-3-one, propanal and methanol. The count is 5.