Out of all the possible isomers of `C_(5)H_(11)Cl`, how many are secondary in nature?
(Exclude stereoisomers if any.)

Answer

To determine how many secondary isomers exist for the compound \( C_5H_{11}Cl \), we need to follow these steps:

### Step 1: Understand the definition of secondary carbon
A secondary carbon is defined as a carbon atom that is bonded to two other carbon atoms. In the context of isomers of \( C_5H_{11}Cl \), we need to identify which of the carbon atoms in the structure can be classified as secondary when a chlorine atom is attached.

**Hint:** Remember that for a carbon to be secondary, it must be attached to two other carbons.

### Step 2: Identify the possible carbon skeletons
For \( C_5H_{11}Cl \), we can have various carbon skeletons. The main carbon chain can be linear or branched. The possible carbon skeletons include:
1. Pentane (straight chain)
2. Isopentane (branched)
3. Neopentane (more branched)

**Hint:** Consider both straight-chain and branched structures when drawing the carbon skeletons.

### Step 3: Draw the structures and identify secondary carbons
Now, let's draw the possible isomers and identify the secondary carbons:

1. **Isomer 1: n-Pentane**
- Structure: \( CH_3-CH_2-CH_2-CH_2-CH_3 \)
- Chlorine can be attached to the second carbon: \( CH_3-CH(Cl)-CH_2-CH_2-CH_3 \) (Secondary)

2. **Isomer 2: Isopentane**
- Structure: \( CH_3-CH(CH_3)-CH_2-CH_3 \)
- Chlorine can be attached to the second carbon: \( CH_3-CH(Cl)-CH_2-CH_3 \) (Secondary)

3. **Isomer 3: 2-Methylbutane**
- Structure: \( CH_3-CH_2-CH(CH_3)-CH_3 \)
- Chlorine can be attached to the second carbon: \( CH_3-CH(Cl)-CH(CH_3)-CH_3 \) (Secondary)

4. **Isomer 4: 2,2-Dimethylpropane**
- Structure: \( (CH_3)_2C(CH_3)-CH_3 \)
- Chlorine cannot be attached to a secondary carbon here.

### Step 4: Count the secondary isomers
From the above structures, we find that the following isomers have secondary carbons:
- Isomer 1: 1 secondary isomer
- Isomer 2: 1 secondary isomer
- Isomer 3: 1 secondary isomer

Thus, there are **3 secondary isomers** of \( C_5H_{11}Cl \).

### Final Answer
The total number of secondary isomers of \( C_5H_{11}Cl \) is **3**.

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