Dipole-dipole, dipole-induced dipole and dispersion forces are collectively called as …………………………….

Answer

To answer the question, "Dipole-dipole, dipole-induced dipole and dispersion forces are collectively called as …………………………….," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Types of Forces**:
- We need to recognize the three types of intermolecular forces mentioned: dipole-dipole forces, dipole-induced dipole forces, and dispersion forces (also known as London dispersion forces).

2. **Definition of Each Force**:
- **Dipole-Dipole Forces**: These occur between molecules that have permanent dipoles. The positive end of one dipole is attracted to the negative end of another dipole.
- **Dipole-Induced Dipole Forces**: These occur when a polar molecule (with a dipole) induces a dipole in a nonpolar molecule by distorting its electron cloud.
- **Dispersion Forces (London Dispersion Forces)**: These are weak forces that arise from temporary dipoles that occur in all molecules due to the movement of electrons.

3. **Collective Term for These Forces**:
- All three types of forces are categorized under the broader term **Van der Waals forces**. This term encompasses all types of intermolecular attractions that are not due to ionic or covalent bonds.

4. **Final Answer**:
- Therefore, the collective term for dipole-dipole, dipole-induced dipole, and dispersion forces is **Van der Waals forces**.