Empirical formula from skeletal structure atom counts

Steps:

• Count carbon atoms at skeleton intersections and chain ends.
• Count explicit nitrogen atoms in the structure.
• Infer hydrogen atoms to complete valences (4 for C, 3 for N, with bonds shown or implied).
• Simplify the C:H:N ratio to lowest whole numbers.

Why B is correct:

• The structure's atom ratio simplifies to 1:4:2 per carbon, yielding CH₄N₂ as the empirical formula.

Why the others are wrong:

• A: Ratio 1:1:1 undercounts H and N relative to structure.
• C: Ratio 1:12:4 reflects molecular formula (C₆H₁₂N₄), not simplest empirical.
• D: Ratio 1:6:4 mismatches the actual simplified H and N counts.

Final answer: B