CAIE A-Level Chemistry AS 17.1.6 Iodoform Test for Ch3co Group Questions

Practise the CAIE 9701 alkaline iodine test for methyl carbonyls, identifying CH3CO– and predicting CHI3 and carboxylate products.

Exam points

locate CH3CO– in an aldehyde or ketone before predicting a positive alkaline-I2 test
state that a pale-yellow or yellow precipitate of CHI3 forms in a positive reaction
draw the second carbon-containing product as the correct RCO2− ion after cleavage

[Maximum number: 1]

X is a non-cyclic ketone with a single carbonyl group and no other functional groups. Ketone X has the following properties.
- When ketone X is treated with $\mathrm{NaBH}_{4}$ , the organic product has a $M_{\mathrm{r}} 2.3256 \%$ greater than the $M_{r}$ of ketone X .
- Ketone X gives a yellow precipitate with alkaline $\mathrm{I}_{2}(\mathrm{aq})$ .

How many isomeric ketones could be ketone X ?

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CAIE A-Level Chemistry AS 17.1.6 Iodoform Test for Ch3co Group Questions question 1