Give the structural formula of 2-methylpentanal.

Answer

To find the structural formula of 2-methylpentanal, we will follow these steps:

### Step 1: Identify the Parent Chain
The name "pentanal" indicates that the parent chain consists of 5 carbon atoms (pent-). Since it is an aldehyde, the functional group (-CHO) is located at the end of the chain.

### Step 2: Draw the Parent Chain
We will draw a straight chain of 5 carbon atoms. The carbon atoms will be numbered from 1 to 5, starting from the end where the aldehyde group is attached (position 1).

```
C1 - C2 - C3 - C4 - C5
```

### Step 3: Add the Aldehyde Group
Since it is an aldehyde, we will place the aldehyde group (-CHO) at the first carbon (C1).

```
O
||
C1 - C2 - C3 - C4 - C5
```

### Step 4: Identify and Add the Methyl Group
The name "2-methyl" indicates that there is a methyl group (-CH3) attached to the second carbon (C2). We will add this methyl group to C2.

```
O
||
C1 - C2 - C3 - C4 - C5
|
CH3
```

### Step 5: Complete the Carbon Chain with Hydrogens
Now, we will add hydrogen atoms to each carbon to satisfy the tetravalency of carbon (each carbon should form four bonds):

- C1 (aldehyde) will have 1 hydrogen.
- C2 will have 1 hydrogen (because it has one bond with the methyl group).
- C3 will have 2 hydrogens.
- C4 will have 2 hydrogens.
- C5 will have 3 hydrogens.

The complete structure will look like this:

```
O
||
H-C1 - C2 - C3 - C4 - C5
|
CH3
```

### Final Structural Formula
The structural formula of 2-methylpentanal can be represented as:

```
O
||
H-C - CH - CH2 - CH3
|
CH3
```