Which of the following compounds contains 8 unique protons in each molecule?

• A. H2O
• B. O2
• C. CO2
• D. SO2

Answer: (D)

Verified step by step guidance

1. Understand that 'unique protons' refers to hydrogen atoms in different chemical environments within a molecule. Each unique proton experiences a distinct electronic environment, making it distinguishable in techniques like NMR spectroscopy.
2. Examine each compound to identify the number of hydrogen atoms and whether they are in unique environments: H2O has 2 hydrogens, O2 and CO2 have none, and SO2 has no hydrogens either, so none of these have 8 unique protons based on hydrogen count.
3. Since the question likely refers to unique proton environments, consider that only molecules containing hydrogen atoms can have unique protons. Therefore, compounds without hydrogen atoms cannot have unique protons.
4. If the question is about unique protons in a different context (such as protons in the nucleus of atoms in the molecule), count the number of chemically distinct hydrogen atoms or consider the molecular symmetry to determine uniqueness.
5. Conclude that among the given options, none contain 8 unique protons in the sense of hydrogen atoms in different environments; thus, the correct answer must be a molecule with 8 hydrogens in unique environments, which is not listed here. SO2 does not contain hydrogen atoms, so it cannot have 8 unique protons.