Give the structural formula of 4-bromo-3-methylpentanal.

Answer

To draw the structural formula of 4-bromo-3-methylpentanal, we will follow these steps:

### Step 1: Identify the main chain
The name "pentanal" indicates that the main carbon chain consists of 5 carbon atoms. The suffix "anal" indicates that the aldehyde functional group (-CHO) is present at the end of the chain.

### Step 2: Draw the 5-carbon chain
We will draw a straight chain of 5 carbon atoms:
```
C1 - C2 - C3 - C4 - C5
```

### Step 3: Position the aldehyde group
Since the aldehyde group is at position 1 (as indicated by the name), we will place it on the first carbon:
```
O
||
C1 - C2 - C3 - C4 - C5
```
The aldehyde group is represented as -CHO, which is attached to C1.

### Step 4: Identify and place the substituents
According to the name, we have:
- A bromine group (bromo) at position 4
- A methyl group (methyl) at position 3

We will add these substituents to the appropriate positions on the carbon chain:
- At C3, we will add a methyl group (-CH3).
- At C4, we will add a bromine atom (Br).

The structure now looks like this:
```
O
||
C1 - C2 - C3 - C4 - C5
| |
CH3 Br
```

### Step 5: Complete the structure with hydrogen atoms
Now we need to add hydrogen atoms to each carbon to satisfy the tetravalency of carbon:
- C1 (aldehyde) has 1 hydrogen.
- C2 has 2 hydrogens.
- C3 has 1 hydrogen (due to the methyl group).
- C4 has 1 hydrogen (due to the bromine).
- C5 has 3 hydrogens.

The complete structure is:
```
O
||
H-C1 - C2 - C3 - C4 - C5
| | |
H CH3 Br
|
H
```

### Final Structural Formula
The final structural formula of 4-bromo-3-methylpentanal is:
```
O
||
H-C-C-C-CH2-CH3
| |
CH3 Br
```