Given the following generic structure: $R-X-Y=Z$, choose the most likely identities for $X$, $Y$, and $Z$ that would result in a carbonyl functional group.

• A. X is $C$, Y is $O$, Z is $C$
• B. X is $C$, Y is $O$, Z is $C$
• C. X is $C$, Y is $O$, Z is $C$
• D. X is $C$, Y is $O$, Z is $O$

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the structure of a carbonyl functional group. A carbonyl group consists of a carbon atom double bonded to an oxygen atom, represented as C=O.
2. Step 2: Analyze the generic structure given: R - X - Y = Z. Here, R is a generic alkyl or aryl group, and X, Y, Z are atoms or groups to be identified to form a carbonyl.
3. Step 3: Identify which atoms correspond to the carbon and oxygen in the carbonyl. Since the carbonyl is C=O, the atom involved in the double bond (Z) must be oxygen (O), and the atom bonded to R (X) must be carbon (C).
4. Step 4: Recognize that Y is the atom connected to both X and Z. In the carbonyl group, the double bond is between carbon and oxygen, so Y must be oxygen (O) to represent the double bond correctly.
5. Step 5: Conclude that for the structure R - X - Y = Z to represent a carbonyl, X should be carbon (C), Y should be oxygen (O), and Z should be carbon (C), reflecting the carbonyl carbon double bonded to oxygen.