Out of three isomeric pentanes, ______ has the maximum bp. and ________has the maximum m.p.

Answer

To solve the question regarding the boiling point (bp) and melting point (mp) of the three isomeric pentanes, we need to consider the structures of the isomers and how their branching affects these physical properties.

### Step-by-Step Solution:

1. **Identify the Isomeric Pentanes**:
The three isomeric forms of pentane are:
- **n-Pentane** (or simply pentane): A straight-chain alkane with the formula C5H12.
- **Isopentane** (or methylbutane): A branched-chain alkane with one branch.
- **Neopentane** (or dimethylpropane): A more branched structure with two branches.

2. **Understanding Boiling Point (bp)**:
- The boiling point of alkanes generally decreases with increased branching. This is because branched alkanes have a more compact structure, leading to weaker van der Waals forces between molecules.
- In this case, n-pentane has the least branching, followed by isopentane, and then neopentane, which is the most branched.

3. **Conclusion for Boiling Point**:
- Therefore, n-pentane has the highest boiling point among the three isomers, while neopentane has the lowest boiling point.
- **Answer**: n-Pentane has the maximum boiling point.

4. **Understanding Melting Point (mp)**:
- The melting point is influenced by how well the molecules can pack together in a solid state. More symmetrical and compact structures tend to have higher melting points.
- Neopentane, being the most compact and symmetrical, will have the best packing efficiency, leading to a higher melting point compared to the other isomers.

5. **Conclusion for Melting Point**:
- Thus, neopentane has the highest melting point among the three isomers.
- **Answer**: Neopentane has the maximum melting point.

### Final Answers:
- n-Pentane has the maximum boiling point.
- Neopentane has the maximum melting point.