Which is incorrectly given according to order indicated?

Options

A. `F_(2) gt Cl_(2) gt Br_(2) gt l_(2),`Oxidising power
B. `Hl gt HBr gt HCl gt HF`: Acidic strength
C. `F_(2) gt Cl_(2) gt Br_(2) gt l_(2)`, Bond dissociation enthalpy
D. `HF gt Hl gt HBr gt HCl`, Boiling point

Answer

To solve the question regarding the incorrect order indicated for the properties of halogens and hydrogen halides, we will analyze each provided order step by step.

### Step-by-Step Solution:

1. **Oxidizing Power of Halogens**:
- The order given is: \( F_2 > Cl_2 > Br_2 > I_2 \).
- Explanation: Fluorine has the highest oxidizing power due to its small size and high electronegativity, making it the strongest oxidizing agent. Chlorine follows, then bromine, and iodine has the least oxidizing power.
- **Conclusion**: This order is correct.

2. **Acidic Strength of Hydrogen Halides**:
- The order given is: \( HI > HBr > HCl > HF \).
- Explanation: The acidic strength increases down the group due to the increasing size of the halide ions, which makes them better leaving groups. Iodine (I-) is the best leaving group, followed by bromine (Br-), chlorine (Cl-), and fluorine (F-), which is the weakest due to its small size and strong bond with hydrogen.
- **Conclusion**: This order is correct.

3. **Bond Dissociation Enthalpy**:
- The order given is: \( F_2 > Cl_2 > Br_2 > I_2 \).
- Explanation: Bond dissociation enthalpy refers to the energy required to break a bond. As we move down the group, the size of the atoms increases, leading to longer bond lengths and therefore lower bond dissociation enthalpy. However, \( F_2 \) has a weaker bond due to electron-electron repulsion in the small fluorine atoms, making it easier to break than \( Cl_2 \). Thus, the correct order should be \( Cl_2 > Br_2 > F_2 > I_2 \).
- **Conclusion**: This order is incorrect.

4. **Boiling Points of Hydrogen Halides**:
- The order given is: \( HF > HI > HBr > HCl \).
- Explanation: The boiling point is influenced by intermolecular forces. HF exhibits hydrogen bonding, which is stronger than the van der Waals forces present in the other hydrogen halides. HI has a larger size, leading to stronger van der Waals forces compared to HBr and HCl.
- **Conclusion**: This order is correct.

### Final Answer:
The incorrectly given order is for bond dissociation enthalpy, which is option C: \( F_2 > Cl_2 > Br_2 > I_2 \).