In gaseous state, ionic character is greatest in

Options

A. HBr
B. HF
C. HCI
D. HI

Answer

To determine which compound has the greatest ionic character in the gaseous state, we need to analyze the electronegativity differences among the halogen compounds formed with hydrogen.

### Step-by-Step Solution:

1. **Understanding Ionic Character**: Ionic character refers to the degree to which a bond between two atoms has ionic characteristics. It is influenced by the difference in electronegativity between the two atoms involved in the bond. The greater the difference, the more ionic character the bond will exhibit.

2. **Identify the Halogen Compounds**: The relevant compounds formed with hydrogen are:
- HF (Hydrogen Fluoride)
- HCl (Hydrogen Chloride)
- HBr (Hydrogen Bromide)
- HI (Hydrogen Iodide)

3. **Electronegativity Values**: The electronegativity values for the elements involved are approximately:
- Hydrogen (H): 2.1
- Fluorine (F): 4.0
- Chlorine (Cl): 3.0
- Bromine (Br): 2.8
- Iodine (I): 2.5

4. **Calculate the Electronegativity Differences**:
- For HF: |4.0 - 2.1| = 1.9
- For HCl: |3.0 - 2.1| = 0.9
- For HBr: |2.8 - 2.1| = 0.7
- For HI: |2.5 - 2.1| = 0.4

5. **Compare the Differences**: The calculated differences show that HF has the highest difference in electronegativity (1.9), followed by HCl (0.9), HBr (0.7), and HI (0.4).

6. **Conclusion**: Since HF has the greatest difference in electronegativity, it exhibits the highest ionic character among the given compounds in the gaseous state.

### Final Answer:
In the gaseous state, the ionic character is greatest in **HF (Hydrogen Fluoride)**.