Answer:
Carbons 1 and 3
Explanation:
We must remember that by definition alpha carbons are the carbon (or carbons) next to the carbon that contains the main group. In this case, the main group is the carbonyl group (C = O) in the middle of the molecule. In the acetone molecule, we have three carbons, the carbons neighboring the carbon of the carbonyl group (carbon two) will be the alpha carbons. (Red and blue carbons or carbons one and three)
See figure 1 for further explanations.
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