Question

Which of the following does not answer iodoform test?
(a) n-butyl alcohol
(b) Acetophenone
(c) Acetaldehyde
(d) Ethylmethyl ketone

Answer 1

Iodoform test:

The iodoform test identifies the presence of a CH₃CO group in aldehydes and ketones and the presence of (CH₃)RCH-OH group in alcohols s it will be oxidized to (CH₃)RC=O by I₂ and NaOH and give positive iodoform test . In the reaction of ketones , aldehydes with  I₂ and NaOH, the H on the CH₃ groups are substituted with I to form I₃C-CO-R, which hydrolyze to form I₃CH (iodoform) as a pale yellow precipitate this can be seen through the image attached.

Here, acetophenone ,  acetaldehyde  and ethylmethyl ketone, all will give positive positive iodoform test because all are having  CH₃CO present.

But the n-butyl alcohol will not give positive iodoform test as it does not have (CH₃)RCH-OH group that can be oxidized to CH₃CO.

Here the answer will be a that is n-butyl alcohol.

Answer 2

Answer:

Explanation:

Iodoform test give those have CH3CO group . Thus ethyl methyl ketone does not have this group so it is right option.