Estimation of ozone can be made quantitatively by :

Options

A. decomposition into `O_(2)` and absorption of `O_(2)` into pyragallol
B. volumetric method using `Kl` and titration of the liberated iodine using hypo solution
C. oxidative ozonolysis method
D. all methods given above

Explanation

To estimate ozone quantitatively, we can utilize several methods. Here’s a step-by-step breakdown of the methods mentioned:

### Step 1: Decomposition into Oxygen and Absorption by Pyrogallol
1. **Method Description**: Ozone can decompose into oxygen gas. In this method, the ozone is allowed to decompose, and the resulting oxygen is absorbed by pyrogallol.
2. **Measurement**: By weighing the pyrogallol before and after the absorption of oxygen, we can determine the amount of ozone present. This is because the decrease in weight of the pyrogallol corresponds to the amount of oxygen absorbed, which is directly related to the amount of ozone that decomposed.

### Step 2: Volumetric Method Using Potassium Iodide
1. **Reaction**: When ozone reacts with potassium iodide (KI) in the presence of water, it produces potassium hydroxide (KOH), oxygen (O2), and iodine (I2).
- **Chemical Equation**:
\[ \text{O}_3 + 2 \text{KI} + \text{H}_2\text{O} \rightarrow 2 \text{KOH} + \text{O}_2 + \text{I}_2 \]
2. **Titration**: The liberated iodine (I2) can then be titrated using a sodium thiosulfate (hypo) solution.
- **Chemical Equation**:
\[ 2 \text{S}_2\text{O}_3^{2-} + \text{I}_2 \rightarrow \text{S}_4\text{O}_6^{2-} + 2 \text{I}^- \]
3. **Quantitative Analysis**: By knowing the amount of sodium thiosulfate used in the titration, we can calculate the amount of iodine produced, and consequently, the amount of ozone that reacted.

### Step 3: Oxidative Ozonolysis Method
1. **Method Description**: This method involves the oxidative ozonolysis of alkenes or other compounds where ozone reacts to form products.
2. **Measurement**: The increase in mass of the reaction mixture can be measured, which is directly proportional to the amount of ozone that has reacted. This allows for a quantitative estimation of ozone.

### Conclusion
All the methods mentioned above can be used for the quantitative estimation of ozone. Therefore, the correct answer is that all methods given above are correct.

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