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

Options

A. (1) Acidic chloride of oxy acids increases with increasis n.
B. (2) Oxidising power of oxy acids increases with decreasis n.
C. (3) Thermal stability oxy acids decreases with increasis n.
D. (4) Cl - O bond order decreases with decreasis n.

Explanation

To determine the incorrect statement regarding the oxyacids of chlorine (HClO_n) where n ranges from 1 to 4, we need to analyze the properties of these acids systematically.

### Step-by-Step Solution:

1. **Identify the Oxyacids**:
The series of oxyacids for chlorine are:
- HClO (n=1)
- HClO2 (n=2)
- HClO3 (n=3)
- HClO4 (n=4)

2. **Acidic Strength**:
The acidic strength of these oxyacids increases with increasing oxidation state of chlorine. The oxidation states are:
- HClO: +1
- HClO2: +3
- HClO3: +5
- HClO4: +7
Thus, the order of acidic strength is:
- HClO < HClO2 < HClO3 < HClO4
This statement is **true**.

3. **Oxidizing Power**:
The oxidizing power of these oxyacids decreases with increasing n. Therefore, the order of oxidizing power is:
- HClO > HClO2 > HClO3 > HClO4
This is because the stability of the acids increases with n, leading to lower oxidizing power. This statement is **true**.

4. **Thermal Stability**:
The thermal stability of these oxyacids generally increases with increasing n. Thus, the statement that thermal stability decreases with increasing n is **false**. Therefore, this is the incorrect statement.

5. **Bond Order**:
The bond order of Cl-O bonds in these acids increases with increasing n. As n increases, the bond order changes from a single bond in HClO to a double bond in HClO3 and HClO4. Thus, the statement that Cl-O bond order decreases with decrease in n is **true**.

### Conclusion:
The incorrect statement regarding the oxyacids HClO_n is that "the thermal stability of oxy-acids decreases with increases in n."