The ionic bond `X^(+)Y^(-)` are formed when :
(I) electron affinity of Y is high (II) ionization energy of X is low
(III) lattice energy of XY is high (IV) lattice energy of XY is low
Choose the correct code :

Options

A. I and II
B. I and III
C. I, II and III
D. All

Answer

To determine the conditions under which the ionic bond \(X^+Y^-\) is formed, we need to analyze each of the statements provided in the question.

### Step-by-Step Solution:

1. **Understanding Ionic Bond Formation**:
- An ionic bond is formed when one atom donates an electron to another atom. This typically occurs between metals (which lose electrons) and non-metals (which gain electrons).

2. **Analyzing Statement I**:
- **Electron Affinity of Y is High**:
- A high electron affinity means that the atom Y has a strong tendency to gain an electron. This is favorable for the formation of an ionic bond because it allows Y to easily accept the electron from X, forming \(Y^-\).
- **Conclusion**: This statement is true.

3. **Analyzing Statement II**:
- **Ionization Energy of X is Low**:
- A low ionization energy means that it requires less energy to remove an electron from atom X. This is favorable for the formation of an ionic bond because X can easily lose its outermost electron to form \(X^+\).
- **Conclusion**: This statement is true.

4. **Analyzing Statement III**:
- **Lattice Energy of XY is High**:
- Lattice energy is the energy released when gaseous ions combine to form an ionic solid. A high lattice energy indicates a strong attraction between the ions, leading to a more stable ionic compound.
- **Conclusion**: This statement is true.

5. **Analyzing Statement IV**:
- **Lattice Energy of XY is Low**:
- A low lattice energy would imply weaker attractions between the ions, resulting in a less stable ionic compound. This is not favorable for the formation of a strong ionic bond.
- **Conclusion**: This statement is false.

### Final Conclusion:
Based on the analysis, the correct statements are:
- I (Electron affinity of Y is high)
- II (Ionization energy of X is low)
- III (Lattice energy of XY is high)

Thus, the correct code is **1, 2, 3**.