Among the isomers of `C_5H_11Cl`, the one which is chiral is
(i) 2,2-Dimethy-1-chloropropane
(ii) 2-Chloropentane
(iii) 2-Methyl-2-chlorobutane
(iv) 3-Chloropentane

Options

A. (i) and (ii) only
B. (i),(ii) and (iii) only
C. (i) and (iii) only
D. (ii) only

Answer

To determine which isomer of C₅H₁₁Cl is chiral, we need to analyze each of the given compounds for the presence of a chiral center. A chiral center is typically a carbon atom that is bonded to four different groups.

Let's evaluate each option step by step:

### Step 1: Analyze 2,2-Dimethyl-1-chloropropane
- **Structure**: The structure can be represented as:
```
CH3
|
CH3 - C - Cl
|
CH2 - CH3
```
- **Chirality Check**:
- The carbon atom with the chlorine (C) is bonded to two CH₃ groups and two hydrogen atoms (H).
- Since it has two identical groups (CH₃), it cannot be a chiral center.
- **Conclusion**: Not chiral.

### Step 2: Analyze 2-Chloropentane
- **Structure**: The structure can be represented as:
```
CH3
|
CH3 - C - Cl
|
CH2 - CH3
```
- **Chirality Check**:
- The second carbon (C) is bonded to:
- One CH₃ group
- One Cl atom
- One H atom
- One CH₂CH₃ group (the rest of the pentane chain)
- All four groups attached to this carbon are different.
- **Conclusion**: This carbon is a chiral center, making 2-chloropentane chiral.

### Step 3: Analyze 2-Methyl-2-chlorobutane
- **Structure**: The structure can be represented as:
```
CH3
|
CH3 - C - Cl
|
CH2 - CH3
```
- **Chirality Check**:
- The carbon with the chlorine is bonded to:
- Two CH₃ groups
- One Cl atom
- One H atom
- Since it has two identical groups (CH₃), it cannot be a chiral center.
- **Conclusion**: Not chiral.

### Step 4: Analyze 3-Chloropentane
- **Structure**: The structure can be represented as:
```
CH3
|
CH2 - C - Cl
|
CH2 - CH3
```
- **Chirality Check**:
- The third carbon (C) is bonded to:
- One CH₃ group
- One Cl atom
- One H atom
- One CH₂CH₃ group
- All four groups attached to this carbon are different.
- **Conclusion**: This carbon is a chiral center, making 3-chloropentane chiral.

### Final Conclusion:
Among the options given, both 2-chloropentane and 3-chloropentane are chiral, but since the question asks for the one which is chiral, we can conclude that **2-Chloropentane** is the most straightforward answer as it is the first chiral compound identified.

### Answer:
The isomer of C₅H₁₁Cl which is chiral is **2-Chloropentane**.

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