Two liquids isohexane and 3-methylpentane has boiling point `60^@C` and `63^@C`. They can be separated by

Options

A. Simple distillation and isohexane comes out first.
B. Fractional distillation and isohexane comes out first.
C. Simple distillation and 3-Methylpantane comes out first.
D. Fractional distillation and 3-Methylpantane comes out first.

Explanation

To solve the problem of separating isohexane and 3-methylpentane, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Compounds**:
- We have two compounds: isohexane and 3-methylpentane.
- Their boiling points are given as:
- Isohexane: 60°C
- 3-Methylpentane: 63°C

2. **Understand the Structures**:
- Isohexane (2-methylpentane) has the following structure:
```
CH3-CH(CH3)-CH2-CH2-CH3
```
- 3-Methylpentane has the following structure:
```
CH3-CH2-CH(CH3)-CH2-CH3
```

3. **Analyze the Boiling Points**:
- The boiling points of the two liquids are close (60°C and 63°C). This indicates that they are likely to form an azeotrope and have similar physical properties.

4. **Choose the Separation Method**:
- Since the boiling points are relatively close, we can use **fractional distillation** as the method of separation. This technique is effective for separating liquids with boiling points that are within about 25°C of each other.

5. **Determine the Order of Distillation**:
- In fractional distillation, the component with the lower boiling point will vaporize first. Therefore, isohexane (60°C) will distill off before 3-methylpentane (63°C).

6. **Conclusion**:
- The two liquids can be separated by fractional distillation, with isohexane being the first to be collected due to its lower boiling point.

### Final Answer:
Isohexane and 3-methylpentane can be separated by **fractional distillation**, with isohexane coming off first.

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