The IUPAC name for CH$_3$CH$_2$COOCH$_2$CH$_3$ is

Step 1: Analyze the question We need the IUPAC name of the ester CH₃CH₂COOCH₂CH₃.

Step 2: Concept Esters have the general formula RCOOR'. The name is built as:

• R' (the group attached to the oxygen) is named first, as an alkyl group.
• RCOO (the acid part, including the carbonyl carbon) is named second, ending in "-oate".

Step 3: Solution Split the molecule at the C(=O)–O–C linkage:

• Acid part: CH₃CH₂COO– has 3 carbons (CH₃, CH₂, C=O), so it comes from propanoic acid and becomes propanoate.
• Alkyl part: –CH₂CH₃ has 2 carbons, so it is an ethyl group.

Put the alkyl group first, then the acid part:

ethyl propanoate

Step 4: Check the other options

• A. methylpropanoate: the alkyl group would be CH₃, but ours is ethyl. ✗
• B. ethylethanoate: the acid part would have only 2 carbons. ✗
• D. methylethanoate: both parts are wrong. ✗

**Answer: C.

Exam tip: Count the carbons on each side of the "–COO–". The side that includes the C=O carbon gives the "-oate" name, and the side attached to the oxygen gives the alkyl name that comes first. Remember it as "alkyl first, acid second".