The increasing order of the acidity of the following acid `I=H_(2)SO_(3), II=H_(3)PO_(3) and III=HCIO_(3)`

Options

A. `I gt III gt II`
B. `II < I < III`
C. `III gt II gt I`
D. `II gt III gt I`

Explanation

To determine the increasing order of acidity for the acids \( H_2SO_3 \) (sulfurous acid), \( H_3PO_3 \) (phosphorous acid), and \( HClO_3 \) (chloric acid), we will analyze the oxidation states of the central atoms in these acids and their corresponding anion stability.

### Step-by-Step Solution:

1. **Identify the Acids**:
- The acids in question are:
- \( H_2SO_3 \) (sulfurous acid)
- \( H_3PO_3 \) (phosphorous acid)
- \( HClO_3 \) (chloric acid)

2. **Draw the Structures**:
- \( H_2SO_3 \) has the structure:
```
O
||
HO-S-OH
|
O
```
- \( H_3PO_3 \) has the structure:
```
O
||
HO-P-OH
|
H
```
- \( HClO_3 \) has the structure:
```
O
||
HO-Cl=O
|
O
```

3. **Determine the Oxidation States**:
- For \( H_2SO_3 \):
- Sulfur (S) has an oxidation state of +4.
- For \( H_3PO_3 \):
- Phosphorus (P) has an oxidation state of +3.
- For \( HClO_3 \):
- Chlorine (Cl) has an oxidation state of +5.

4. **Analyze Acidity Based on Oxidation States**:
- The acidity of oxoacids generally increases with the increase in the oxidation state of the central atom. This is because a higher oxidation state leads to a greater positive charge, which stabilizes the conjugate base formed after the acid donates a proton (H⁺).
- Therefore, we compare the oxidation states:
- \( H_2SO_3 \) (S: +4)
- \( H_3PO_3 \) (P: +3)
- \( HClO_3 \) (Cl: +5)

5. **Rank the Acids by Acidity**:
- The order of acidity from least to most acidic based on oxidation states is:
- \( H_3PO_3 \) (least acidic, +3)
- \( H_2SO_3 \) (moderately acidic, +4)
- \( HClO_3 \) (most acidic, +5)

6. **Final Increasing Order of Acidity**:
- Thus, the increasing order of acidity is:
\[ H_3PO_3 < H_2SO_3 < HClO_3 \]