Which is not incorrect ?

Options

A. Stability order
`H-O-underset(O)underset(||)overset(O)overset(||)(S)-O-HltH-O-underset(O)underset(darr)overset(O)overset(uarr)(S)-O-H`
B. In `XeF_(6)(s)` hybridisation of cation `tosp^(3)`d
C. For `O_(2)` molecule bond order is 2.0
D. Bond angle order `CF_(4)ltCH_(4)`

Answer

To solve the question "Which is not incorrect?" we need to analyze each statement provided in the context of chemistry and determine which one is correct.

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks us to identify which statement is "not incorrect," meaning we are looking for a correct statement among the options provided.

2. **Analyzing Statement 1**:
- The statement discusses the stability of two structures of sulfuric acid (H₂SO₄). It mentions that sulfur can have a +6 oxidation state due to the availability of empty 3d orbitals for backbonding with oxygen.
- The conclusion drawn is that both representations of sulfuric acid have the same stability, which is stated to be incorrect. Therefore, this statement is not the correct answer.

**Hint**: Check the stability of different resonance structures and their contributions to the overall stability.

3. **Analyzing Statement 2**:
- This statement involves the hybridization of the cation XeF₅⁺. It states that XeF₆ ionizes to form XeF₅⁺ and F⁻.
- The hybridization is calculated based on the number of valence electrons. The conclusion is that XeF₅⁺ has sp³d² hybridization, which is stated to be incorrect. Thus, this statement is also not the correct answer.

**Hint**: Remember to consider the total number of valence electrons and how they contribute to hybridization.

4. **Analyzing Statement 3**:
- This statement calculates the bond order of O₂ using the molecular orbital theory. The bond order is calculated as the difference between the number of bonding and antibonding electrons divided by two.
- The calculation shows that the bond order of O₂ is 2, which is indeed correct. Therefore, this statement is the correct answer.

**Hint**: Use the formula for bond order correctly and ensure to account for all bonding and antibonding electrons.

5. **Analyzing Statement 4**:
- This statement compares the bond angles of CF₄ and CH₄. Both molecules are tetrahedral and exhibit sp³ hybridization.
- The conclusion drawn is that the bond angles are the same (109.5°) due to symmetrical repulsion. However, it incorrectly states that one bond angle is greater than the other, which is not true. Therefore, this statement is also not the correct answer.

**Hint**: Consider the effects of lone pairs and bond angles in tetrahedral geometries.

### Conclusion:
After analyzing all statements, the only statement that is correct is Statement 3, which pertains to the bond order of O₂.

### Final Answer:
The correct answer is **Option 3**.