Consider the oxy acids `HClO_n` series here value of n is 1 to 4. then incorrect statement regarding these oxyacids Is:

Options

A. Acidic character of oxy acids increases with increasing value of n.
B. Oxidising power of oxy acids increases with decreasing value of n
C. thermal stability of oxy acids decreases with increasing value of n.
D. Cl-O' bond order decreases with decreasing value of n

Explanation

To determine the incorrect statement regarding the oxyacids \( HClO_n \) (where \( n \) ranges from 1 to 4), we will analyze each statement based on the properties of these oxyacids.

### Step-by-Step Solution:

1. **Identify the Oxyacids**: The oxyacids in the series are:
- \( HClO \) (Hypochlorous acid)
- \( HClO_2 \) (Chlorous acid)
- \( HClO_3 \) (Chloric acid)
- \( HClO_4 \) (Perchloric acid)

2. **Analyze Acidic Character**:
- The acidic character of oxyacids generally increases with the number of oxygen atoms attached to the central atom (chlorine in this case).
- The order of acidity is:
- \( HClO_4 > HClO_3 > HClO_2 > HClO \)
- **Conclusion**: The statement that "the acidic character of oxyacid increases with increasing value of \( n \)" is **correct**.

3. **Analyze Oxidizing Power**:
- The oxidizing power of these oxyacids generally decreases with increasing \( n \) because the higher the oxidation state of chlorine, the lower its ability to act as an oxidizing agent.
- The order of oxidizing power is:
- \( HClO > HClO_2 > HClO_3 > HClO_4 \)
- **Conclusion**: The statement that "the oxidizing power of oxyacids increases with decreasing value of \( n \)" is **correct**.

4. **Analyze Thermal Stability**:
- The thermal stability of these oxyacids increases with increasing \( n \).
- The order of thermal stability is:
- \( HClO_4 > HClO_3 > HClO_2 > HClO \)
- **Conclusion**: The statement that "the thermal stability of oxyacids decreases with increasing value of \( n \)" is **incorrect**.

5. **Analyze Bond Order**:
- The bond order of the Cl-O bond decreases as \( n \) decreases.
- The order of bond order is:
- \( HClO_4 > HClO_3 > HClO_2 > HClO \)
- **Conclusion**: The statement that "the chlorine-oxygen bond order decreases with decreasing value of \( n \)" is **correct**.

### Final Conclusion:
The incorrect statement regarding these oxyacids is:
- **"The thermal stability of oxyacids decreases with increasing the value of \( n \)"** (Option 3).