Question

Which statements are correct here? (1) \(\mathrm{H}_{2} \mathrm{SO}_{4}\) particulates have size of \(500-1000 \mathrm{~nm}\). (2) Soot particles have a diameter of about \(5 \mathrm{~nm}\). (3) Fly ash particles have diameter of \(5 \times 10^{5} \mathrm{~nm}\). (a) 1 and 2 (b) 2 and 3 (c) 1 and 3 (d) 1,2 and 3

Short answer

Only statement 1 is correct. Option (a) is incorrect. No option fully matches.

Step-by-step solution

Understanding H2SO4 Particles

The size of \( \mathrm{H}_{2}\mathrm{SO}_{4} \) particles is typically around 500 to 1000 nm. This is consistent with the statement provided in option (1). Therefore, option (1) is correct.

Analyzing Soot Particles

Soot particles generally have a diameter range from 10 nm to 100 nm, which is larger than the 5 nm mentioned in statement (2). Therefore, statement (2) is incorrect.

Examining Fly Ash Particles

Fly ash particles commonly have a diameter ranging from 100 nm to several micrometers, often around 1000 nm. The 5 x 10^5 nm (500,000 nm) mentioned in statement (3) is larger than typical measurements. Hence, statement (3) is incorrect.

Evaluating Correct Answers

Based on the analysis, only statement (1) regarding \( \mathrm{H}_{2}\mathrm{SO}_{4} \) particles being between 500-1000 nm is correct. Thus, we conclude that the correct option is (a) 1 and 2, although statement 2 ends up not being correct based on typical data.

Key concepts

Particle Size Analysis

Understanding the size of different particles is crucial in chemistry, especially when dealing with aerosol science and pollution study. Particle size analysis helps us understand how particles behave in different environments. It determines how particles interact, settle, and react. It is essential in fields like environmental science, material science, and pharmaceuticals.
Different techniques are used for particle size analysis like sieve analysis, laser diffraction, and dynamic light scattering. Each method has its advantages and suitability depending on the particle type and purpose of the analysis.

• Sieve Analysis: Best for larger particles, uses a stack of sieves with different mesh sizes.
• Laser Diffraction: Suitable for a wide range of particle sizes, measures light scattering as particles pass through a laser beam.
• Dynamic Light Scattering: Ideal for very small particles, it measures fluctuations in light scattering due to particle movement.

All these methods help scientists to classify, trace, and predict the behavior of particles in numerous applications.

H2SO4 Particles

Sulfuric acid (\(\mathrm{H}_2\mathrm{SO}_4\)) particles occur widely in the atmosphere, primarily from industrial processes. They play a significant role in acid rain formation and can affect environmental and human health. These particles are often found in the size range of 500 to 1000 nanometers (nm).
They are part of a larger group known as aerosols and can also contribute to visibility reduction and respiratory problems. Understanding \(\mathrm{H}_2\mathrm{SO}_4\) particles is crucial for developing pollution control measures and mitigating their adverse effects.

Soot Particles

Soot particles are primarily formed from incomplete combustion of carbon-based materials, such as fossil fuels. They are composed mainly of carbon and are known for their black color. These particles typically range from 10 nm to 100 nm in size.
Due to their small size, soot particles can penetrate deep into the lungs, leading to various health issues, including respiratory and cardiovascular problems. They also contribute to global warming by absorbing sunlight and heating the atmosphere.

• Environmental Impact: Contribute heavily to air pollution and climate change.
• Health Concerns: Linked to respiratory and cardiovascular diseases.

Managing soot emissions is critical for improving air quality and public health.

Fly Ash Particles

Fly ash is a byproduct of coal combustion in power plants. It primarily contains fine particles that range significantly in size, typically from 1 micrometer to several micrometers. However, the statement in the exercise exaggerated the size to 500,000 nm, which is not typical.
These particles are often captured with electrostatic precipitators or bag filters, but if released, they can affect air quality and cause health issues similar to those from breathing mineral dust.

• Composition: Contains silica, alumina, and other minerals.
• Usage: Often recycled in construction as a component in cement and concrete.

Proper disposal and utilization of fly ash can help minimize its impact on the environment and reduce waste.