Question

In stratosphere, which of the following elements acts as a catalyst in degradation of ozone and release of molecular oxygen ?

• A. Carbon
• B. Fe
• C. Cl
• D. Oxygen

Answer 1

The Correct Option is C

The question pertains to the element that acts as a catalyst in the degradation of ozone in the stratosphere. The correct answer is chlorine (Cl).

Here's a detailed explanation:

1. Understanding the Role of Ozone in the Stratosphere:
   • Ozone (O₃) is a molecule composed of three oxygen atoms, and it forms a layer in the stratosphere that protects life on Earth by absorbing the majority of the Sun's harmful ultraviolet (UV) radiation.
2. Catalytic Degradation of Ozone:
   • The ozone layer can be degraded by certain chemicals, each acting as a catalyst. A catalyst is a substance that speeds up a chemical reaction without itself undergoing any permanent chemical change.
   • Chlorofluorocarbons (CFCs), used in refrigeration and aerosols, release chlorine atoms when broken down by UV radiation.
3. Role of Chlorine (Cl):
   • When CFCs reach the stratosphere, they are broken down by UV light, releasing chlorine atoms.
   • These chlorine atoms catalyze the decomposition of ozone, forming molecular oxygen (O₂). The reaction can be represented as follows:
   Cl + O_3 \rightarrow ClO + O_2
   • The chlorine monoxide (ClO) can further react with another ozone molecule to release more chlorine, perpetuating the cycle:
   ClO + O_3 \rightarrow Cl + 2O_2
4. Eliminating Other Options:
   • Carbon: It does not act as a catalyst in ozone depletion.
   • Iron (Fe): Not involved in stratospheric ozone degradation.
   • Oxygen: While a part of ozone's composition, it does not degrade ozone; rather, it forms part of the catalytic cycle that breaks down ozone when released from the ozone splitting reaction.
5. Conclusion:
   • Chlorine (Cl) is the element that acts as a catalyst in the degradation of the ozone layer, confirming it as the correct option.