An isomer of `C_(5)H_(12)` gives total six isomeric products on monochlorination. Calculate the percentage yield of the primary monochloride which is chiral. Consider the following relative reactivity of `C-H` bonds for chlorination.
`|{:("Degree of "C-H,1^(@) C-H,2^(@) C-H,3^(@) C-H),("Relative reactivity for chlorination (R R)",1,3,5):}|`

Explanation

To solve the problem, we need to follow these steps:

### Step 1: Identify the isomer of C5H12
We are given that the compound is an isomer of C5H12. The possible isomers include:
1. Pentane
2. 2-Methylbutane
3. 3-Methylbutane
4. 2,2-Dimethylpropane
5. 2,3-Dimethylbutane

For this problem, we will consider 2-Methylbutane as the isomer since it has a primary carbon that can yield a chiral monochloride.

### Step 2: Determine the number of isomeric products from monochlorination
When monochlorination occurs, we need to consider the relative reactivity of the C-H bonds:
- Primary C-H: 1
- Secondary C-H: 3
- Tertiary C-H: 5

In 2-Methylbutane, the chlorination can occur at:
- 1° (primary) C-H: 6 hydrogens (C1 and C5)
- 2° (secondary) C-H: 2 hydrogens (C2)
- 3° (tertiary) C-H: 1 hydrogen (C3)

### Step 3: Calculate the total reactivity
Using the relative reactivity values:
- For primary C-H: 6 (hydrogens) × 1 (reactivity) = 6
- For secondary C-H: 2 (hydrogens) × 3 (reactivity) = 6
- For tertiary C-H: 1 (hydrogen) × 5 (reactivity) = 5

Total reactivity = 6 (primary) + 6 (secondary) + 5 (tertiary) = 17

### Step 4: Calculate the percentage yield of the primary monochloride which is chiral
The primary monochloride that is chiral comes from the chlorination of the primary C-H bonds. The yield can be calculated as follows:

\[ \text{Percentage yield of primary monochloride} = \left( \frac{\text{Yield from primary C-H}}{\text{Total reactivity}} \right) \times 100 \]

Substituting the values:
\[ \text{Percentage yield} = \left( \frac{6}{17} \right) \times 100 \approx 35.29\% \]

### Step 5: Final answer
The percentage yield of the primary monochloride which is chiral is approximately **35.29%**.

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