Science & Technology·Prelims Questions

Environmental Chemistry — Prelims Questions

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Version 1Updated 9 Mar 2026

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Q1medium

Which of the following statements about the ozone layer depletion is/are correct? 1. Chlorofluorocarbons (CFCs) release chlorine atoms in the stratosphere upon exposure to UV radiation. 2. Chlorine atoms catalytically destroy ozone molecules. 3. Polar Stratospheric Clouds (PSCs) play a role in enhancing ozone depletion. Select the correct answer using the code given below:

Q2medium

Consider the following statements regarding Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD): 1. BOD measures the oxygen required for microbial decomposition of biodegradable organic matter. 2. COD measures the total oxygen equivalent for oxidation of all organic and inorganic substances. 3. BOD values are typically higher than COD values for the same water sample. Which of the statements given above is/are correct?

Q3easy

Which of the following is NOT a principle of Green Chemistry?

Q4medium

Photochemical smog is primarily formed due to the interaction of sunlight with which of the following pairs of pollutants?

Q5easy

Which of the following government initiatives in India is directly linked to improving air quality through chemical understanding and control of particulate matter, SO2, and NOx?