Polarization involves the distortion of the shape of an anion by an adjacently placed cation. In this context, which of the following statements is correct ?

Options

A. Maximum polarization is done by a cation of high charge
B. A large cation is likely to bring large degree of polarization
C. A smaller anion is likely to undergo a high degree of polarization
D. Minimum polarization is done by a cation of small size

Answer

To solve the question about polarization and the distortion of an anion by an adjacent cation, we will analyze the statements provided and determine which one is correct based on the principles of chemical bonding and polarization.

### Step-by-Step Solution:

1. **Understanding Polarization**:
- Polarization refers to the distortion of the electron cloud of an anion due to the electric field created by a nearby cation. The cation attracts the electron density of the anion, leading to a change in its shape.

**Hint**: Recall that polarization involves the interaction between charged species, where one can distort the electron cloud of the other.

2. **Polarizing Power of Cations**:
- The polarizing power of a cation is influenced by its charge and size. Specifically, it is directly proportional to the ionic charge and inversely proportional to the ionic size. This means that a cation with a higher charge and smaller size will have a greater ability to polarize an anion.

**Hint**: Remember the relationship: higher charge = higher polarizing power; larger size = lower polarizing power.

3. **Polarizability of Anions**:
- The polarizability of an anion is influenced by its size. Larger anions have more diffuse electron clouds, making them easier to polarize. Conversely, smaller anions are less polarizable.

**Hint**: Consider how the size of an anion affects its electron cloud and its ability to be distorted.

4. **Evaluating the Options**:
- **Option 1**: "Maximum polarization is done by the cation of high charge."
- This statement is correct because a cation with a higher charge will exert a stronger attractive force on the electron cloud of the anion, leading to greater polarization.

- **Option 2**: "A large cation is likely to bring a large degree of polarization."
- This statement is incorrect. Larger cations have lower polarizing power due to their size, which reduces their ability to distort the anion.

- **Option 3**: "A smaller anion is likely to undergo a high degree of polarization."
- This statement is also incorrect. Smaller anions are less polarizable because their electron clouds are more tightly held.

- **Option 4**: "Minimum polarization is done by a cation of small size."
- This statement is incorrect. Smaller cations have higher polarizing power, not minimum polarization.

5. **Conclusion**:
- Based on the analysis, the correct statement is **Option 1**: "Maximum polarization is done by the cation of high charge."

### Final Answer:
The correct statement is **Option 1: Maximum polarization is done by the cation of high charge.**