London Dispersion force is present between :-

Options

A. Polar + Polar molecules
B. Nonpolar + Non-polar molecules
C. Polar+ Nonpolar molecules
D. Ionic

Answer

**Step-by-Step Solution:**

1. **Understanding London Dispersion Forces**:
- London dispersion forces are a type of intermolecular force that arise due to the temporary fluctuations in electron density within molecules. These fluctuations can create temporary dipoles, which induce dipoles in neighboring molecules.

2. **Identifying Characteristics**:
- London dispersion forces are the weakest of all intermolecular forces.
- They are present in all molecules, but they are particularly significant in non-polar molecules where other types of intermolecular forces (like dipole-dipole interactions or hydrogen bonding) are absent.

3. **Recognizing the Types of Molecules**:
- Non-polar molecules do not have a permanent dipole moment. Examples include noble gases (like helium, neon), diatomic molecules (like O2, N2), and hydrocarbons (like methane, CH4).

4. **Conclusion**:
- Since London dispersion forces are primarily significant in non-polar molecules, the correct answer to the question "London Dispersion force is present between:" is that they are present between non-polar molecules.

5. **Final Answer**:
- Therefore, the correct option is **B** (assuming option B refers to non-polar molecules).

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