Problem 61 - A Complete Resource Book in Chemistry for JEE Main

Question

Which air pollutant is not released by automobiles? (a) fly ash (b) \(\mathrm{CO}\) (c) \(\mathrm{SO}_{2}\) (d) hydrocarbons

Step-by-Step Solution

Answer

Fly ash is not released by automobiles.

Step 1: Understanding the Question

The question asks which of the given pollutants is not emitted by automobiles. We need to evaluate each option to determine which pollutants are typically released by vehicles and which are not.

Step 2: Evaluating Each Option

Let's consider each option: (a) Fly ash - This is generally emitted from industrial sources, such as power plants that burn coal, not from cars. (b) CO - Carbon Monoxide is a common pollutant from car exhaust due to incomplete combustion. (c) SO2 - Sulfur Dioxide can be emitted by cars, especially if the fuel contains sulfur. (d) hydrocarbons - These are emitted by cars as unburnt or partially burnt fuel.

Step 3: Identifying the Correct Answer

After evaluating each option: - Fly ash (a) is not typically emitted by automobiles. It is associated with coal-burning activities in industrial settings. - Options (b), (c), and (d) are all common automotive emissions. Therefore, fly ash is not released by automobiles.

Key Concepts

Automotive Emissions

Automotive emissions refer to the pollutants emitted by vehicles as they burn fuel. Common pollutants include:

• Carbon Monoxide (CO): A colorless, odorless gas produced by the incomplete combustion of carbon-containing fuels, such as gasoline. It reduces oxygen delivery in the body, posing health risks.
• Sulfur Dioxide (SO₂): Often released when fuel containing sulfur is burnt. Modern engines minimize this emission due to stricter regulations on fuel sulfur content.
• Hydrocarbons: These are unburnt or partially burnt fuel molecules that can lead to smog formation, posing a threat to both the environment and human health.

Automobiles play a significant role in air pollution due to their widespread use and large numbers. Controlling these emissions is crucial for environmental protection.

Industrial Pollutants

Industrial pollutants are undesired byproducts from industrial processes, released into the environment. Unlike automotive emissions, which primarily arise from vehicles, industrial pollutants originate from manufacturing, power generation, and chemical processing. Key pollutants include:

• Fly Ash: A type of particulate matter primarily from coal-fired power plants. It consists of tiny particles that can harm respiratory health when inhaled.
• Nitrogen Oxides (NOx): Emitted from factories and power plants, these contribute to the formation of acid rain.
• Heavy Metals: Substances like lead and mercury that can be toxic to both humans and wildlife.

The control and reduction of industrial pollutants are vital. They can affect not only air quality but also soil and water, posing risks to entire ecosystems.

Environmental Chemistry

Environmental chemistry is the study of chemical processes both in and influenced by the environment. This field explores how chemical compounds are transformed in air, water, and soil, and their interactions with living organisms.
Key aspects include:

• Air Quality Monitoring: Understanding how pollutants like CO, SO₂, and NOx impact the atmosphere.
• Chemical Reactions: Studying how pollutants react to form secondary compounds, like how hydrocarbons contribute to the formation of ground-level ozone.
• Mitigation Strategies: Developing methods to reduce or eliminate the presence of harmful substances, such as catalytic converters in cars to reduce CO emissions.

Environmental chemistry bridges chemistry with environmental science, offering solutions to modern pollution challenges.

Emission Sources

Emission sources refer to various origins of pollutants released into the atmosphere. Understanding these sources is crucial in managing and reducing emissions.
Key emission sources include:

• Automobiles: A major source of CO, hydrocarbons, and NOx, these are reduced through cleaner fuels and advanced engine technologies.
• Industries: Include everything from power generation to chemical manufacturing, often emitting pollutants like fly ash and SO₂.
• Agricultural Activities: Emissions from fertilizers and livestock can release ammonia and methane into the atmosphere.

Identifying and controlling emission sources are pivotal in improving air quality and addressing global environmental issues like climate change.