Question

Iodoform can be prepared from all except:
A. Acetaldehyde
B. \[3 - \]methyl\[ - 2 - \]butanone
C. Isobutyl alcohol
D. Acetophenone

Answer 1

Hint: Iodoform is an organoiodine compound with the formula \[{\text{CH}}{{\text{I}}_3}\].
We can synthesize iodoform using organic compounds having aldehyde or ketone group i.e carbonyl group having a methyl group on the side.

Complete step by step answer:
We can perform iodoform reaction using any of these four kinds of organic compounds \[i.e\]. a Methyl ketone (\[{\text{C}}{{\text{H}}_3}{\text{COR}}\]) or acetaldehyde (\[{\text{C}}{{\text{H}}_3}{\text{CHO}}\]) or ethanol (\[{\text{C}}{{\text{H}}_3}{\text{C}}{{\text{H}}_2}{\text{OH}}\]) or secondary alcohol. As all of the above mentioned organic compounds contain group or group.
Now, we will see the reaction scheme of iodoform reaction.

So, from the above discussion, we understand that the compound having an aldehydic group or -methyl ketone group will give this reaction.
Now, we will see the structure of the given compound.

So, from the above structures, we can easily find out that all compounds except Isobutyl alcohol are having the required groups mentioned in the hint i.e aldehydic group or ketonic group with methyl on the side.
So, only the isobutyl alcohol will not give response to the iodoform test.
So, Iodoform can be prepared from all except isobutyl alcohol.
So, the correct option is option\[ - \left( {\mathbf{C}} \right).\]

Note:
1. Iodoform is a pale yellow colored, volatile substance and has a distinctive odor.
2. Like iodoform, there are chloroform and bromoform also. All the reactions go via the same mechanism.
3. While performing the iodoform reaction, care must be taken because of the corrosiveness of iodine.