What effect does branching of an alkane chain has on its boiling point?

Explanation

### Step-by-Step Solution:

1. **Understanding Alkanes and Boiling Points**:
- Alkanes are hydrocarbons with the general formula CnH2n+2. They are saturated compounds and consist of carbon and hydrogen atoms linked by single bonds.
- The boiling point of a substance is the temperature at which its vapor pressure equals the external pressure, leading to the transition from liquid to gas.

2. **Intermolecular Forces in Alkanes**:
- Alkanes primarily experience Van der Waals forces (also known as London dispersion forces), which are weak intermolecular forces that arise due to temporary dipoles in molecules.
- The strength of these forces is influenced by the surface area of the molecules. Larger surface areas allow for more contact between molecules, leading to stronger Van der Waals forces.

3. **Effect of Branching on Surface Area**:
- As the branching of an alkane chain increases, the overall surface area of the molecule decreases.
- For example, consider straight-chain alkanes versus branched alkanes. A straight-chain alkane has a larger surface area compared to its branched counterpart.

4. **Impact on Boiling Point**:
- With a decrease in surface area due to branching, the intermolecular Van der Waals forces become weaker.
- Weaker intermolecular forces require less energy (lower temperature) to overcome, resulting in a lower boiling point for branched alkanes compared to their straight-chain isomers.

5. **Conclusion**:
- Therefore, the effect of branching in an alkane chain is that it leads to a decrease in the boiling point due to reduced surface area and weaker Van der Waals forces.

### Summary:
In summary, as the branching of an alkane chain increases, the boiling point decreases because the surface area of the molecule decreases, leading to weaker intermolecular Van der Waals forces.

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