Chapter Exam

Chapter 15: Environmental Chemistry — Online MCQ Test

Q: Which layer of the atmosphere contains the ozone layer?

Answer: B. Stratosphere — The ozone layer is primarily located in the stratosphere, protecting life from harmful UV radiation.

Q: What is the permissible level of fluoride ions in drinking water according to WHO?

Answer: A. 1 ppm — Excess fluoride beyond 1 ppm causes mottling of teeth and skeletal fluorosis.

Q: Acid rain is primarily caused by the emission of:

Answer: B. Sulfur dioxide and nitrogen oxides — SO2 and NO2 react with atmospheric water to form sulfuric and nitric acids, resulting in acid rain.

Q: Which statement about photochemical smog is INCORRECT?

Answer: C. It is a reducing smog. — Photochemical smog is an oxidizing smog, whereas sulfurous (London) smog is a reducing smog.

Q: In the mechanism of ozone depletion, the catalyst for the reaction is:

Answer: B. Cl radical — The chlorine radical (Cl·) acts as the chain carrier and catalyst that reacts with ozone, regenerating itself in the process.

CHEMISTRY · CLASS 11th · Tamil Nadu State Board

Practice Chapter 15: Environmental Chemistry with a free chapter-wise online MCQ test for Tamil Nadu State Board CLASS 11th CHEMISTRY. This chapter covers: The final chapter details atmospheric water and soil pollution greenhouse effect global warming and ozone depletion mechanics. Students explore industrial waste control green chemi.... AI-generated questions from basic to board-exam level, with instant results and explanations.

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Chapter 15: Environmental Chemistry — Important Questions & Answers (FAQ)

Frequently asked questions from Tamil Nadu State Board CLASS 11th CHEMISTRY — Chapter 15: Environmental Chemistry, with answers and explanations. These are sample questions; the exam has its own separate question set.

Which layer of the atmosphere contains the ozone layer?

A. Troposphere
B. Stratosphere ✓
C. Mesosphere
D. Thermosphere

Answer: B. Stratosphere
The ozone layer is primarily located in the stratosphere, protecting life from harmful UV radiation.

What is the permissible level of fluoride ions in drinking water according to WHO?

A. 1 ppm ✓
B. 5 ppm
C. 10 ppm
D. 20 ppm

Answer: A. 1 ppm
Excess fluoride beyond 1 ppm causes mottling of teeth and skeletal fluorosis.

Acid rain is primarily caused by the emission of:

A. CFCs and methane
B. Sulfur dioxide and nitrogen oxides ✓
C. Carbon monoxide and dust
D. Ozone and hydrocarbons

Answer: B. Sulfur dioxide and nitrogen oxides
SO2 and NO2 react with atmospheric water to form sulfuric and nitric acids, resulting in acid rain.

Which statement about photochemical smog is INCORRECT?

A. It occurs in warm, dry and sunny climates.
B. It contains ozone, nitric oxide, and PAN.
C. It is a reducing smog. ✓
D. It results from reactions of hydrocarbons and nitrogen oxides in sunlight.

Answer: C. It is a reducing smog.
Photochemical smog is an oxidizing smog, whereas sulfurous (London) smog is a reducing smog.

In the mechanism of ozone depletion, the catalyst for the reaction is:

A. ClO radical
B. Cl radical ✓
C. O2 molecule
D. CF2Cl2 molecule

Answer: B. Cl radical
The chlorine radical (Cl·) acts as the chain carrier and catalyst that reacts with ozone, regenerating itself in the process.