The IUPAC name of C2H6COOC2,/sub>H6 is

The formula is garbled ("C2H6COOC2,/sub>H6"), so we first need to work out what was intended.

Step 1: Interpret the formula The most likely intended formula is C₂H₅COOC₂H₅. Subscripts of 6 are impossible for an ethyl group, which must be C₂H₅. (Note: the written "C2H6" is a typo for C₂H₅.)

Step 2: Recall how esters are named An ester has the general form R-COO-R'.

• The R' group (attached to the O) is named first, as an alkyl name.
• The R-COO part (the acid part) is named second, ending in "-oate".

Step 3: Identify each part

• Acid part: C₂H₅COO-. This has the carbon chain of the carboxyl carbon plus the C₂H₅ group, which is 3 carbons in total, so it comes from propanoic acid and is named propanoate.
• Alkyl part: -C₂H₅ is ethyl.

Step 4: Combine the names The name is ethyl propanoate.

Step 5: Check against the options

• A. "ethyethanoate" would be CH₃COOC₂H₅, which has 2 carbons in the acid part, so it does not match.
• B. "ethylproanoate" is a misspelling of ethyl propanoate, but it is clearly the intended option.
• C. Propyl ethanoate is CH₃COOC₃H₇, so it does not match.
• D. Propyl propanoate is C₂H₅COOC₃H₇, so it does not match.

Exam tip: Name an ester "backwards" from how it is written. Read the part after the O first (alkyl), then name the acid part and change "-oic acid" to "-oate". Count the carbons of the acid part including the C=O carbon.