The number of cyclic ketones of molecular formula `C_(3)H_(4)O` are:

Options

A. 2
B. 1
C. 3
D. 4

Answer

To determine the number of cyclic ketones with the molecular formula \( C_3H_4O \), we can follow these steps:

### Step 1: Understanding the Molecular Formula
The molecular formula \( C_3H_4O \) indicates that there are 3 carbon atoms, 4 hydrogen atoms, and 1 oxygen atom.

### Step 2: Identifying Possible Cyclic Structures
Cyclic ketones are cyclic compounds that contain a carbonyl group (C=O) within a ring structure. The smallest cyclic structure that can be formed with 3 carbon atoms is a three-membered ring, known as cyclopropane.

### Step 3: Introducing the Ketone Functional Group
To form a cyclic ketone from cyclopropane, we need to replace one of the CH2 groups with a carbonyl group (C=O). This results in a structure where the carbonyl group is part of the ring.

### Step 4: Drawing the Structure
1. Start with cyclopropane:
\[ \text{C} - \text{C} - \text{C} \]
Each carbon is bonded to two hydrogen atoms.

2. Replace one CH2 with a carbonyl group:
\[ \text{C} - \text{C} - \text{C=O} \]
The remaining two carbons will still be bonded to hydrogen atoms:
\[ \text{C} - \text{C} - \text{C=O} \]
This gives us the cyclic ketone structure.

### Step 5: Confirming the Number of Cyclic Ketones
After analyzing the structure, we find that only one cyclic ketone can be formed from \( C_3H_4O \), which is cyclopropanone.

### Conclusion
Thus, the number of cyclic ketones that can be formed from the molecular formula \( C_3H_4O \) is **1**.