Empirical formula from skeletal structure

Steps:

• Examine the skeletal formula to identify carbon atoms (junctions and ends), assuming standard organic notation.
• Count hydrogen atoms, adding implied ones to carbons (each C has 4 bonds).
• Count oxygen atoms shown as O.
• Simplify the molecular formula C_x H_y O_z to lowest ratio.

Why A is correct:

• CHO represents the simplest whole-number ratio of 1C:1H:1O, matching the atom count in Y's skeletal formula per empirical formula definition.

Why the others are wrong:

• B, C, D (all CH2O): Show 1:2:1 ratio, which overcounts H relative to Y's structure.

Not enough information: No diagram provided to verify atom counts. Final answer: A