What is the oxidation number of the carbonyl carbon in acetaldehyde (ethanal, CH3-CHO)? -2 -1 0 +1 +2

The oxidation number of the carbonyl carbon in acetaldehyde (ethanal, CH3-CHO) is +1.

Here's the step-by-step explanation:

1. The oxidation state of hydrogen is +1 and that of oxygen is -2.
2. In acetaldehyde, the carbonyl carbon is bonded to one hydrogen and one oxygen atom, and it's also bonded to a carbon atom.
3. The carbon-hydrogen bond doesn't change the oxidation state, so we can ignore it.
4. The carbon-oxygen double bond would contribute -2 to the oxidation state of the carbonyl carbon because oxygen is more electronegative.
5. The bond with the other carbon atom doesn't change the oxidation state, so we can ignore it.
6. Therefore, the oxidation state of the carbonyl carbon is +1.