Question

Which of the following statements are correct? (1) Ammonia acts as a sink for \(\mathrm{NOx}\). (2) The average residence time of \(\mathrm{NO}\) is one month. (3) SOx can be removed from flue gases by passing through a solution of citrate ions. (4) Limestone acts as a sink for \(S O x\). (a) 1,3 and 4 (b) 1,2 and 4 (c) 2,3 and 4 (d) 1,2 and 3

Short answer

None of the provided options are completely correct.

Step-by-step solution

Analyze Statement (1)

Ammonia (Ox]) being a sink implies it can neutralize or remove NOx from the environment. Generally, ammonia reacts with NOx in atmospheric processes or industrial applications to form ammonium nitrate or ammonium sulfate, acting effectively as a sink. Statement (1) is correct.

Examine Statement (2)

The average residence time for nitric oxide (O]) in the atmosphere is usually much shorter than one month, typically ranging from a few hours to a few days due to its high reactivity. Thus, statement (2) is incorrect.

Evaluate Statement (3)

SOx, or sulfur oxides, can indeed be removed from flue gases through various processes. However, using a citrate ion solution is not typical for the removal of SOx. Lime or limestone slurry is generally more common for scrubbing sulfur oxides. Statement (3) is incorrect.

Assess Statement (4)

Limestone can combine with sulfur oxides (Ox]) to produce calcium sulfate, effectively removing SOx from gases. This lime or limestone scrubbing process is widely used in industrial applications. Therefore, statement (4) is correct.

Determine Correct Statements

Based on the analysis: Statements (1) and (4) are correct. Statements (2) and (3) are incorrect. Thus, option (a) 1, 3, and 4 has incorrect statements; option (b) 1, 2, and 4 has one incorrect; option (c) 2, 3, and 4 has two incorrect; therefore, none of the given options have all correct statements.

Key concepts

Environmental Chemistry

Environmental Chemistry is the study of chemical processes occurring in the environment, impacted by both natural factors and human activities. This field focuses on understanding how chemicals affect natural systems like the air, water, and soil. Environmental chemistry plays a crucial role in identifying and solving environmental problems.
It extends to the development of green chemistry practices to prevent environmental contamination. Understanding the chemistry behind natural and man-made environmental changes allows us to create effective strategies for pollution reduction and resource conservation.

• Emphasis on sustainable chemical practices
• Focus on the impacts of industrial chemicals
• Development of eco-friendly technologies

By applying the knowledge gained through environmental chemistry, we can monitor and manage pollutants, contributing to a healthier planet.

Air Pollution

Air pollution refers to the presence of harmful or excessive quantities of substances in the air. These pollutants can include gases like sulfur oxides (SOx), nitrogen oxides (NOx), and particulate matter that originate from various sources such as vehicles, power plants, and industrial emissions. Air pollution poses severe risks to human health and the environment.
The adverse effects of air pollution can range from respiratory issues in humans to broader environmental impacts such as acid rain and climate change.

• Main sources include transportation and industrial activities
• Effects on health include diseases like asthma and other respiratory conditions
• Environmental impacts include ecosystem damage and reduced visibility

Mitigating air pollution involves regulations to limit emissions, development of cleaner technology, and public awareness.

Sulfur Oxides Removal

Sulfur oxides, primarily sulfur dioxide (SO₂), are major contributors to air pollution, especially from the burning of fossil fuels. Sulfur oxides can lead to acid rain, which can harm ecosystems and structures. Removing these oxides is essential for reducing pollution and its harmful effects.
The flue gas desulfurization process is one effective method in industrial applications for removing SOx. This process often involves the use of limestone or lime to scrub sulfur oxides from exhaust gases, producing gypsum as a byproduct.

• Limestone scrubbing transforms SOx into calcium sulfate
• Citrate ion solutions are not typically used for SOx removal
• Sulfur oxides removal reduces acid rain and improves air quality

By implementing more efficient SOx removal techniques, industries can significantly reduce their environmental impact.