Question

The minimum number of carbon atoms which a ketone may contain is

Answer 1

First member of Ketone is propanone.
CH3-C-CH2
...........||
..........O
Prop suffix is used when we have three carbon atoms. Therefore, minimum number of carbon atoms in ketone is 3.
Note: Please ignore the dots in the structure of propanone given above.

Thanks.

Answer 2

a compound should have at least 3 carbon atoms to belong to a ketone group