Which of the following properties does not correspond to the order given below: `HI < HBr < HCI

Options

A. Thermal stability
B. Reducing power
C. Ionic character
D. Dipole moment

Answer

To solve the question regarding the order of properties for the hydrogen halides (HI < HBr < HCl < HF), we need to analyze the properties of these compounds and identify which one does not follow the expected trend.

### Step-by-Step Solution:

1. **Understanding the Compounds**:
- The compounds in question are hydrogen halides: HI (hydrogen iodide), HBr (hydrogen bromide), HCl (hydrogen chloride), and HF (hydrogen fluoride).

2. **Analyzing the Bond Strength**:
- As we move down the group from HF to HI, the bond length increases due to the larger size of the halogen atoms. This results in weaker bonds.
- Therefore, the bond strength order is: HF > HCl > HBr > HI.

3. **Thermal Stability**:
- The thermal stability of these hydrogen halides decreases as we go from HF to HI. This means that HI is the least thermally stable and HF is the most thermally stable.

4. **Reducing Power**:
- The reducing power of hydrogen halides increases as we move down the group. This is because larger halides (like Iodine in HI) can lose electrons more easily than smaller halides (like Fluorine in HF).
- Thus, the order of reducing power is: HI > HBr > HCl > HF.

5. **Identifying the Incorrect Property Order**:
- The order given in the question (HI < HBr < HCl < HF) does not correspond to the reducing power, as the correct order for reducing power is HI > HBr > HCl > HF.
- Therefore, the property that does not correspond to the order given is the reducing power of the hydrogen halides.

### Conclusion:
The property that does not correspond to the order given (HI < HBr < HCl < HF) is the reducing power of these compounds.