The `pK_a` of oxoacids of chlorine in water follows the order

Options

A. `HClO lt HClO_3 lt HClO_2 lt HClO_4`
B. `HClO_4 lt HClO_3 lt HClO_2 lt HClO`
C. `HClO_4 lt HClO_2 lt HClO_3 lt HClO`
D. `HClO_2 lt HClO lt HClO_3 lt HClO_4`

Explanation

To determine the order of the `pK_a` values of the oxoacids of chlorine in water, we need to analyze the structure and oxidation states of the chlorine in these acids. The relevant oxoacids of chlorine include:

1. **HClO** (Hypochlorous acid)
2. **HClO2** (Chlorous acid)
3. **HClO3** (Chloric acid)
4. **HClO4** (Perchloric acid)

### Step 1: Understand the Oxidation States
The oxidation states of chlorine in these acids are as follows:
- In HClO, the oxidation state of Cl is +1.
- In HClO2, the oxidation state of Cl is +3.
- In HClO3, the oxidation state of Cl is +5.
- In HClO4, the oxidation state of Cl is +7.

### Step 2: Relate Oxidation State to Acidity
The acidity of oxoacids generally increases with the increase in the oxidation state of the central atom (in this case, chlorine). This is because a higher oxidation state leads to a stronger positive charge on the chlorine, which can stabilize the negative charge on the conjugate base after deprotonation.

### Step 3: Determine the Order of Acidity
Based on the oxidation states, we can predict the order of acidity (or inversely, the order of `pK_a` values):
- HClO (Cl at +1) < HClO2 (Cl at +3) < HClO3 (Cl at +5) < HClO4 (Cl at +7)

This means that:
- HClO has the highest `pK_a` (least acidic)
- HClO2 has a lower `pK_a`
- HClO3 has an even lower `pK_a`
- HClO4 has the lowest `pK_a` (most acidic)

### Step 4: Write the Final Order of `pK_a`
Thus, the order of `pK_a` values of the oxoacids of chlorine in water is:
**HClO > HClO2 > HClO3 > HClO4**

### Summary of Steps
1. Identify the oxoacids of chlorine.
2. Determine the oxidation states of chlorine in each acid.
3. Relate the oxidation state to the acidity of the acids.
4. Write the order of `pK_a` based on the acidity.