3-Butenoic acid (for But-3-enoic acid) is represented as :

Options

A.
B.
C.
D. none of these

Answer

To represent 3-butenoic acid (or but-3-enoic acid) structurally, we can follow these steps:

### Step 1: Identify the Base Structure
The name "butenoic acid" indicates that the base structure is a butanoic acid, which consists of 4 carbon atoms. The "oic acid" suffix indicates the presence of a carboxylic acid group (-COOH).

### Step 2: Determine the Position of the Double Bond
The "3" in "3-butenoic acid" indicates that the double bond is located between the 3rd and 4th carbon atoms.

### Step 3: Draw the Carbon Chain
Start by drawing a straight chain of 4 carbon atoms:
```
C1 - C2 - C3 - C4
```

### Step 4: Add the Carboxylic Acid Group
Attach the carboxylic acid group (-COOH) to the first carbon (C1):
```
O
||
C1 - C2 - C3 - C4
|
OH
```

### Step 5: Add the Double Bond
Now, we need to add the double bond between C3 and C4:
```
O
||
C1 - C2 - C3 = C4
|
OH
```

### Step 6: Complete the Valencies
Now, complete the valencies of the carbon atoms with hydrogen atoms:
- C1 has 1 hydrogen (since it is bonded to -COOH).
- C2 has 2 hydrogens.
- C3 has 1 hydrogen (due to the double bond with C4).
- C4 has 2 hydrogens.

The final structure looks like this:
```
O
||
H-C1 - C2 - C3 = C4
| | |
H H H
```

### Final Structural Representation
The final structural representation of 3-butenoic acid (but-3-enoic acid) is:
```
O
||
HOOC - C1 - C2 - C3 = C4
```