The number of `1^(@), 2^(@)`, and `3^(@) H` atoms in 3-ethy1-5-methy1 heptane, respectively , is:

Options

A. 12,8,1
B. 14,4,2
C. 12,6,2
D. 12,8,2

Explanation

To determine the number of primary (1°), secondary (2°), and tertiary (3°) hydrogen atoms in 3-ethyl-5-methylheptane, we will follow these steps:

### Step 1: Understand the Structure of the Compound
3-ethyl-5-methylheptane is an alkane with a seven-carbon chain (heptane) and two substituents: an ethyl group at the third carbon and a methyl group at the fifth carbon.

### Step 2: Draw the Structure
1. Start by drawing a straight chain of 7 carbon atoms (heptane):
```
C1 - C2 - C3 - C4 - C5 - C6 - C7
```
2. Add the ethyl group (C2H5) at the third carbon (C3):
```
C1 - C2 - C3(C2H5) - C4 - C5 - C6 - C7
```
3. Add the methyl group (CH3) at the fifth carbon (C5):
```
C1 - C2 - C3(C2H5) - C4 - C5(CH3) - C6 - C7
```

### Step 3: Determine the Degree of Each Carbon
- **Primary Carbons (1°)**: Carbons attached to one other carbon.
- **Secondary Carbons (2°)**: Carbons attached to two other carbons.
- **Tertiary Carbons (3°)**: Carbons attached to three other carbons.

### Step 4: Identify Each Carbon in the Structure
- **C1**: Primary (attached to C2)
- **C2**: Secondary (attached to C1 and C3)
- **C3**: Tertiary (attached to C2, C4, and the ethyl group)
- **C4**: Secondary (attached to C3 and C5)
- **C5**: Tertiary (attached to C4, C6, and the methyl group)
- **C6**: Primary (attached to C5 and C7)
- **C7**: Primary (attached to C6)

### Step 5: Count the Hydrogen Atoms
- **Primary Hydrogens (1°)**:
- C1: 3 H
- C6: 3 H
- C7: 3 H
- Total = 3 + 3 + 3 = **9 H**

- **Secondary Hydrogens (2°)**:
- C2: 2 H
- C4: 2 H
- Total = 2 + 2 = **4 H**

- **Tertiary Hydrogens (3°)**:
- C3: 1 H
- C5: 1 H
- Total = 1 + 1 = **2 H**

### Final Count
- Primary Hydrogens: 9
- Secondary Hydrogens: 4
- Tertiary Hydrogens: 2

### Conclusion
The number of 1°, 2°, and 3° hydrogen atoms in 3-ethyl-5-methylheptane is **9, 4, and 2**, respectively.