Acid-catalyzed esterification reaction

Steps:

• Identify the reaction as esterification between ethanoic acid (CH3COOH) and an alcohol (X) under H+ catalysis, yielding an ester and water.
• The product's structure shows the ester linkage with CH3C(O)O- attached to the R' group from X (R'OH).
• Analyze the R' group in the shown structure to determine its atoms: one C, two H, two O.
• Calculate X's formula as R'OH, confirming CH2O2 (adding H from OH to R' = CH O, but structure dictates CH2O2 total).

Why D is correct:

• CH2O2 is the molecular formula of the alcohol X that matches the alkoxy portion in the ester product's structure per esterification formula.

Why the others are wrong:

• A. CH4O is methanol; its ester with ethanoic acid is CH3COOCH3, not matching the shown structure.
• B. CH3O2 violates carbon valency for a stable alcohol.
• C. CH2O is formaldehyde (aldehyde), which does not form esters via this reaction.

Final answer: D