Ester Structure Analysis for Isomer and Alcohol Classification

Steps:

• Examine the double bond in the acid-derived chain of the ester; cis isomer has substituents on the same side.
• Confirm trans would have substituents on opposite sides, but the structure aligns with cis.
• Identify the alcohol-derived alkyl group; the carbon attached to the ester oxygen has two alkyl substituents.
• Classify this carbon: two substituents indicate secondary alcohol.

Why A is correct:

• The ester's double bond shows cis geometry (same-side substituents per alkene isomerism rules), and the alcohol's -CH(R1)(R2)-O- linkage defines a secondary alcohol (carbon with two carbons attached).

Why the others are wrong:

• B: Alcohol is secondary, not tertiary (tertiary requires three alkyl groups on the oxygen-attached carbon).
• C: Geometrical isomer is cis, not trans (trans has opposite-side substituents).
• D: Isomer is cis (not trans) and alcohol is secondary (not tertiary).

Final answer: A