Chemistry 9th Chap 11 : Topic 7 - Maryam Publications

Chemistry Chapter 11 : Topic 7

Nitrogen Oxides and Acid Rain

1 / 20

How do nitrogen oxides (NO and NO₂) contribute directly to acid rain formation?

A) By dissolving in rainwater to form nitric acid

B) By converting into methane in atmosphere

C) By increasing atmospheric oxygen concentration

D) By reacting with oxygen to form carbonic acid

2 / 20

Which acid is formed when nitrogen dioxide reacts with atmospheric moisture?

A) Carbonic acid

B) Hydrochloric acid

C) Sulfuric acid

D) Nitric acid

3 / 20

What is the indirect role of NO₂ in acid rain formation involving sulfur dioxide?

A) It neutralizes SO₂.

B) It catalyzes oxidation of SO₂ into SO₂.

C) It converts SO₂ into oxygen.

D) It removes sulfur from atmosphere.

4 / 20

Why is nitrogen dioxide considered important in the oxidation of sulfur dioxide in the atmosphere?

A) It reduces SO₂ into sulfur.

B) It acts as a catalyst speeding up oxidation reactions.

C) It converts SO₂ into nitrogen gas.

D) It stops formation of acids.

5 / 20

Which sequence correctly shows NOₓ involvement in acid rain formation?

A) NO₂ → O₂ → N₂

B) NO₂ → HNO₃ (formation)

C) NO → CO₂ → H₂O

D) NO → O₂ → H₂O

6 / 20

How do nitrogen oxides act in the atmosphere during sulfur dioxide oxidation?

A) As water absorbers

B) As reducing agents

C) As neutral gases

D) As catalysts accelerating SO₂ oxidation

7 / 20

Which acid is formed when sulfur trioxide reacts with water in presence of NO₂ catalysis?

A) Sulfuric acid

B) Hydrochloric acid

C) Nitric acid

D) Carbonic acid

8 / 20

Why is NO₂ considered a secondary pollutant in acid rain formation?

A) It does not react in atmosphere.

B) It is completely inert in air.

C) It forms from NO oxidation and participates in further reactions.

D) It is directly emitted from natural sources only.

9 / 20

What is the role of NO in atmospheric reactions leading to acid rain?

A) It gets oxidized to NO₂, which contributes to acid formation.

B) It neutralizes acids in rain.

C) It converts oxygen into nitrogen.

D) It directly forms sulfuric acid.

10 / 20

Which combination correctly represents nitrogen oxides involved in acid rain?

A) SO₂ and CO₂

B) NO and CO₂

C) O₂ and NO₂

D) NO and NO₂

11 / 20

How does NO₂ accelerate formation of sulfuric acid in the atmosphere?

A) By catalyzing oxidation of SO₂ to SO₃

B) By decomposing water vapor

C) By converting acids into salts

D) By producing oxygen directly

12 / 20

Which statement best describes the dual role of NOₓ gases in acid rain formation?

A) They prevent acid formation.

B) They only increase oxygen levels.

C) They directly form nitric acid and indirectly help form sulfuric acid.

D) They only reduce atmospheric pollution.

13 / 20

Why are NO and NO₂ considered significant environmental pollutants?

A) They contribute to acid rain formation and respiratory issues.

B) They increase soil fertility.

C) They increase oxygen concentration.

D) They reduce atmospheric temperature.

14 / 20

Which atmospheric process converts NO into NO₂?

A) Reduction by sulfur

B) Oxidation by oxygen

C) Neutralization with water

D) Combustion with carbon

15 / 20

What makes NO₂ important in multi-step acid rain chemistry?

A) It only forms oxygen.

B) It removes sulfur from air.

C) It acts as an intermediate and catalyst in acid-forming reactions.

D) It stops oxidation reactions.

16 / 20

Which gas is directly responsible for formation of nitric acid in atmosphere?

A) Methane

B) Nitrogen

C) Nitrogen dioxide

D) Oxygen

17 / 20

How do NOₓ gases increase environmental acidity?

A) By producing alkaline compounds

B) By increasing oxygen concentration

C) By removing hydrogen ions from water

D) By forming strong acids like nitric acid in rainwater

18 / 20

Which step shows catalytic role of NO₂ in sulfur cycle of atmosphere?

A) H₂O → NO₂ → O₂

B) SO₂ → NO → CO₂

C) SO₂ → SO₃ (with NO₂ assistance)

D) SO₃ → NO₂ → N₂

19 / 20

Why is acid rain formation involving NOₓ considered a chain reaction process?

A) Because only oxygen is involved.

B) Because it stops after one step.

C) Because NOₓ continuously participates in multiple reactions.

D) Because it does not involve water.

20 / 20

Which of the following best summarizes the role of NO and NO₂ in acid rain formation?

A) They form nitric acid directly and catalyze sulfur dioxide oxidation.

B) They only neutralize acids.

C) They reduce greenhouse gases.

D) They convert oxygen into nitrogen.

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