How many methyl groups are present in 2, 5-Dimethyl-4-ethylnonane ?

Options

A. 2
B. 3
C. 4
D. 5

Explanation

To determine how many methyl groups are present in 2,5-Dimethyl-4-ethylnonane, we can follow these steps:

### Step 1: Identify the Parent Chain
The name "2,5-Dimethyl-4-ethylnonane" indicates that the parent chain is nonane, which consists of 9 carbon atoms.

### Step 2: Draw the Parent Chain
Draw a straight chain of 9 carbon atoms:
```
C1 - C2 - C3 - C4 - C5 - C6 - C7 - C8 - C9
```

### Step 3: Add the Substituents
According to the name:
- At the 2nd carbon (C2), there is a methyl group (–CH3).
- At the 5th carbon (C5), there is another methyl group (–CH3).
- At the 4th carbon (C4), there is an ethyl group (–CH2CH3).

### Step 4: Complete the Structure
Now we can complete the structure by adding the substituents:
```
CH3
|
C1 - C2 - C3 - C4 - C5 - C6 - C7 - C8 - C9
| |
CH3 CH2 - CH3
```

### Step 5: Count the Methyl Groups
Now, we need to count the methyl groups in the structure:
1. The methyl group at C2.
2. The methyl group at C5.
3. The terminal methyl group at C1 (from the nonane chain).
4. The terminal methyl group from the ethyl group at C4 (–CH2CH3 contributes one methyl group).

### Conclusion
Adding these up, we have:
- 2 methyl groups from the substituents (at C2 and C5).
- 1 methyl group from the terminal carbon (C1).
- 1 methyl group from the ethyl group (C4).

Thus, the total number of methyl groups in 2,5-Dimethyl-4-ethylnonane is **5**.

### Final Answer
**5 methyl groups are present in 2,5-Dimethyl-4-ethylnonane.**