Final answer:
Upon examining the oxidation states of carbon in oxalic acid and glucose, it is determined that the carbon atoms in glucose have a generally lower oxidation state due to more carbon-hydrogen bonds compared to carbon-oxygen bonds in oxalic acid, resulting in the lowest oxidation number in glucose. The correct answer is b. carbon in glucose.
Step-by-step explanation:
To determine in which of the compounds oxalic acid (H₂C₂O₄) or glucose (C₆H₁₂O₆) carbon has the lowest oxidation number, we examine each compound separately.
For oxalic acid, assigning an oxidation number of +1 to hydrogen and −₂ to oxygen, the two carbons must collectively balance the charge with an oxidation state that results in a neutral compound.
Considering there are four oxygens at −₂ and two hydrogens at +1, the two carbons in oxalic acid result in an oxidation number of +3 for each carbon. For glucose, each carbon is attached to hydrogen and oxygen atoms.
However, since glucose is a polyhydroxy aldehyde, the majority of the carbons are bonded to hydrogens and only one carbon (the aldehyde carbon) is double-bonded to an oxygen. This gives an overall lower oxidation state for carbons in glucose compared to the carbons in oxalic acid.
Therefore, the carbon in glucose has the lowest oxidation number.