Which of the following is a primary halide ?

Options

A. iso-Propyl iodide
B. sec-Buty iodie
C. tert-Butyl bromide
D. neo-Hexyl chloride

Answer

To determine which of the following compounds is a primary halide, we need to analyze the structures of each compound and identify the type of carbon to which the halide (X) is attached. A primary halide is defined as a halide attached to a primary carbon, which is a carbon that is bonded to only one other carbon atom.

Let's analyze the options one by one:

1. **Isopropyl iodide (CH3-CH(I)-CH3)**:
- Structure:
```
CH3
|
CH
|
I
```
- The carbon atom to which the iodine (I) is attached is bonded to two other carbon atoms (the two CH3 groups). Therefore, this is a **secondary halide**.

2. **Secondary butyl iodide (CH3-CH2-CH(I)-CH3)**:
- Structure:
```
CH3
|
CH2
|
CH
|
I
```
- The carbon atom to which the iodine (I) is attached is bonded to two other carbon atoms (the CH3 and CH2 groups). Therefore, this is also a **secondary halide**.

3. **Tertiary butyl bromide (CH3-C(CH3)(Br)-CH3)**:
- Structure:
```
CH3
|
C
/ \
CH3 Br
```
- The carbon atom to which the bromine (Br) is attached is bonded to three other carbon atoms (the two CH3 groups and the central carbon). Therefore, this is a **tertiary halide**.

4. **Neohexyl fluoride (CH3-C(CH3)(CH2-CH2-F)-CH3)**:
- Structure:
```
CH3
|
C
/ \
CH3 CH2
|
F
```
- The carbon atom to which the fluoride (F) is attached is bonded to only one other carbon atom (the CH2 group). Therefore, this is a **primary halide**.

After analyzing all options, we conclude that the primary halide among the given options is **neohexyl fluoride**.

### Final Answer:
**Neohexyl fluoride is the primary halide.**