Consider the following reaction:
`CH_(3)underset(D)underset(|)CH-underset(CH_(3))underset(|)(CH)CH_(3)+overset(.)BrrarrX+HBr`
Identify the structure of the major products `(X)` from among the following :

Options

A. `CH_(3)-underset(D)underset(|)(CH)-underset(CH_(3))underset(|)(CH)-overset(.)CH_(2)`
B. `CH_(3)-underset(D)underset(|)(CH)-underset(CH_(3))underset(|)overset(.)(C)-CH_(3)`
C. `CH_(3)-underset(D)underset(|)(CH)-CH_(3)`
D. `CH-overset(.)CH-underset(CH_(3))underset(|)(CH)-CH_(3)`

Answer

To solve the given problem, we need to analyze the reaction of the compound with bromine radicals and identify the major product formed. Let's break down the steps systematically:

### Step 1: Identify the Structure of the Reactant
The reactant is given as:
\[ \text{CH}_3\text{CHDCH(CH}_3)\text{CH}_3 \]
This structure includes:
- A carbon chain with a deuterium (D) atom.
- The carbon atoms can be classified as primary and secondary based on their bonding.

### Step 2: Understand the Reaction Mechanism
The reaction involves bromine radicals (\( \cdot \text{Br} \)) which will abstract a hydrogen atom from the reactant. This is a free radical substitution reaction.

### Step 3: Determine Possible Hydrogen Abstraction Sites
In the reactant, we have:
- Primary carbons (two CH3 groups).
- Secondary carbons (one CH and one CHD).

The bromine radical can abstract hydrogen from either primary or secondary carbons.

### Step 4: Analyze Stability of the Resulting Radicals
- **Primary Radical**: Less stable.
- **Secondary Radical**: More stable.
- **Tertiary Radical**: Most stable (not applicable here).

Since the most stable radical will form preferentially, we expect the bromine radical to abstract hydrogen from a secondary carbon (the one attached to deuterium).

### Step 5: Predict the Major Product
When the bromine radical abstracts a hydrogen from the secondary carbon (the one with D), we will form a secondary radical. The product will then be:
\[ \text{CH}_3\text{CHD}\cdot\text{C(CH}_3)\text{CH}_3 + \text{HBr} \]

### Step 6: Identify the Correct Option
Now, let's analyze the options provided:
- **Option A**: \( \text{CH}_3\text{CHD}\cdot\text{C(CH}_3)\text{CH}_2 \) - Incorrect, as it suggests a primary radical.
- **Option B**: \( \text{CH}_3\text{CHD}\cdot\text{C(CH}_3)\text{CH}_3 \) - Correct, as it represents the stable secondary radical.
- **Option C**: \( \text{CH}_3\text{CHD}\text{C(CH}_3)\text{H} \) - Incorrect, as it does not show a radical.
- **Option D**: \( \text{CH}\cdot\text{C(CH}_3)\text{CH}_3 \) - Incorrect, as it implies a different structure.

### Conclusion
The major product \( X \) formed from the reaction is represented by **Option B**.