The reaction that give good yield of n-Hexane is :-

Options

A. `undersetoverset(Na//"dry ether")(rarr)(CH_(3)CH_(2))CH_(2)-Cl + CH_(3)CH_(2)CH_(2)Cl`
B. `CH_(3)CH_(2)Cl + CH_(3)CH_(2)CH_(2)CH_(2)Cl overset(Na//"dry ether")rarr`
C. `underset overset(Na//"dry ether")rarr(CH_(3)-Cl)+CH_(3)CH_(2)CH_(2)CH_(2)CH_(2)Cl`
D. All of them

Answer

To determine which reaction gives a good yield of n-hexane, we need to analyze the three reactions provided. All these reactions are types of Wurtz reactions, where two moles of alkyl halides react in the presence of sodium (Na) and dry ether to form alkanes.

### Step-by-Step Solution:

1. **Understanding Wurtz Reaction**:
- The Wurtz reaction involves the coupling of two alkyl halides in the presence of sodium to form a higher alkane. The general reaction can be represented as:
\[ 2 \text{R-X} + 2 \text{Na} \rightarrow \text{R-R} + 2 \text{NaX} \]
- Here, R represents the alkyl group and X represents the halide.

2. **Analyzing the First Reaction**:
- In the first reaction, both alkyl halides are the same (let's say they are both hexyl halides).
- When these two react, they will only form n-hexane (C6H14) without any branching.
- Therefore, the yield of n-hexane will be high since there are no side products.

3. **Analyzing the Second Reaction**:
- In the second reaction, the alkyl halides are different (let's say they are butyl halides).
- The reaction can lead to the formation of multiple products, including butane (C4H10) and octane (C8H18), in addition to n-hexane.
- Since there are side products, the yield of n-hexane will be lower compared to the first reaction.

4. **Analyzing the Third Reaction**:
- In the third reaction, the alkyl halides are methyl halides.
- This reaction can produce ethane (C2H6) and decane (C10H22), along with n-hexane.
- Similar to the second reaction, the presence of side products will decrease the yield of n-hexane.

5. **Conclusion**:
- The first reaction, where both alkyl halides are the same and specifically chosen to be hexyl halides, will give the best yield of n-hexane.
- Therefore, the answer to the question is option (a), which corresponds to the first reaction.

### Final Answer:
The reaction that gives a good yield of n-hexane is option (a).