Identifying the ester structure of propyl methanoate

Steps:

• Esters follow the general formula RCOOR', where R is from the carboxylic acid and R' from the alcohol.
• "Methanoate" indicates the acid part is from methanoic acid (R = H), so HCOO-.
• "Propyl" indicates the alcohol part is propanol (R' = CH₂CH₂CH₃).
• The structure is H-C(=O)-O-CH₂CH₂CH₃.

Why B is correct:

• Option B matches the formula HCOOCH₂CH₂CH₃, the standard structure for propyl methanoate.

Why the others are wrong:

• A represents methyl propanoate (CH₃CH₂CH₂COOCH₃), with reversed alkyl groups.
• C represents butyl methanoate (HCOOCH₂CH₂CH₂CH₃), with a longer alcohol chain.
• D represents ethyl methanoate (HCOOCH₂CH₃), with a shorter alcohol chain.

Final answer: B