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Iodoform Test

I₂/NaOH gives yellow precipitate of CHI₃ with methyl ketones and ethanol. Has antiseptic smell!

How It Works

1

Three Unknown Compounds

Tubes A, B, C contain ethanol/acetaldehyde, methyl ketone, and other ketone.

2

Add I₂ + NaOH

I₂/NaOH gives yellow CHI₃ precipitate with CH₃CO- or CH₃CH(OH)- groups.

3

Observe Precipitate

Yellow ppt + antiseptic smell = Positive. No ppt = Negative.

Reaction Key

Ethanol/CH₃CHO:

Yellow CHI₃ precipitate + antiseptic smell

Methyl Ketone:

Yellow CHI₃ precipitate + antiseptic smell

Other Ketone:

No yellow precipitate