Stratosphere contains a stable layer of ozone molecules which absorbs UV radiation from the sun. The presence of ozone in atmosphere serves, as a shield to protect living organism on earth from the harmful effects of the solar ultraviolet radiation. The ultraviolet radiation are known to cause skin cancer. Ozone is formed in stratosphere by the following photochemical reactions.
`O_(2)(g)overset(UV)rarrO(g)+O(g)`
`O(g)+O_(2)(g)overset(UV)hArrO_(3)(g)`
Ozone is thormodhynamically unstable and ecomposes to molecular oxygen. Thus a dynamic equilibrium exits between the production and decomposition of ozone molecules.
Maximum quantity of ozone is present in

Options

A. Stratosphene
B. Mesosphere
C. Troposphere
D. Thermosphere

Answer

To solve the question regarding the maximum quantity of ozone present in the atmosphere, we will analyze the information provided about the layers of the atmosphere and the formation of ozone.

### Step-by-Step Solution:

1. **Understanding the Layers of the Atmosphere**:
- The atmosphere is divided into several layers: Troposphere, Stratosphere, Mesosphere, and Thermosphere.
- Each layer has distinct characteristics and functions.

2. **Role of Ozone in the Stratosphere**:
- Ozone (O₃) is primarily found in the Stratosphere, which is located approximately 10.6 kilometers to 50 kilometers above the Earth's surface.
- The Stratosphere contains a stable layer of ozone molecules that absorb harmful ultraviolet (UV) radiation from the sun.

3. **Formation of Ozone**:
- Ozone is formed through photochemical reactions involving diatomic oxygen (O₂) and monoatomic oxygen (O).
- The reactions are as follows:
- \( O_2(g) \overset{UV}{\rightarrow} O(g) + O(g) \)
- \( O(g) + O_2(g) \overset{UV}{\rightleftharpoons} O_3(g) \)
- This indicates that ozone is continuously produced and decomposed, establishing a dynamic equilibrium.

4. **Maximum Quantity of Ozone**:
- It is well-established that about 90% of the Earth's ozone is located in the Stratosphere.
- The Stratosphere acts as a protective shield against UV radiation, which is crucial for protecting living organisms on Earth.

5. **Conclusion**:
- Given the information and the understanding of atmospheric layers, the maximum quantity of ozone is present in the **Stratosphere**.

### Final Answer:
The maximum quantity of ozone is present in **Option A: Stratosphere**.

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