Final answer:
The oxidation numbers for carbon compounds can vary depending on the molecule. In CH4, the carbon atom has an oxidation number of -4, whereas in carboxylic acid, it has an oxidation number of +2.
Step-by-step explanation:
In this example, we can calculate the oxidation number for the carbon atom in each case. For CH4, the carbon atom carries a -4 oxidation number. For the alcohol, the carbon atom has an oxidation number of -2. For the aldehyde, the carbon atom's oxidation number is 0. For the carboxylic acid, the carbon atom's oxidation number is +2. And for carbon dioxide, the carbon atom's oxidation number is +4.