Environmental Pollution

Concept: In chemistry and environmental safety, hazardous effects of substances can be reduced by modifying their reactivity. Step 1:Understand protecting groups.
Protecting groups are used to:

• Temporarily block reactive sites
• Reduce unwanted or harmful reactions

Step 2:Evaluate options.}

• Increasing bioavailability Increases effect (incorrect)
• Minimising biodiversity Irrelevant
• Using protecting groups Reduces hazardous reactivity (correct)
• Using solvents Does not necessarily reduce hazard

Final Answer:

Concept: Soil pollution is mainly caused by chemicals introduced through agricultural and industrial activities. Step 1:Identify the major contributor.
Pesticides are widely used in agriculture and:

• Accumulate in soil
• Persist for long periods
• Harm microorganisms and soil fertility

Step 2:Evaluate other options.}

• Radioactive waste Rare and localized
• Nitrates Nutrients, but excess causes pollution (less major)
• Dioxins Toxic but not as widespread as pesticides

Final Answer:

Concept: Leaking gasoline contains several toxic hydrocarbons and additives that contaminate soil and groundwater. Step 1:Identify common gasoline contaminants.}

• Benzene Toxic aromatic hydrocarbon
• Toluene Present in gasoline
• MTBE (methyl tertiary butyl ether) Fuel additive

Step 2:Check ethanol.
Ethanol is used as a fuel additive (blending agent), but it is not typically considered a contaminant in leaking gasoline. Final Answer:

Concept: Air pollutants vary in toxicity depending on their impact on human health, especially the respiratory system. Step 1:Understand asbestos.
Asbestos is a highly toxic air pollutant because:

• Its fine fibers are easily inhaled
• It causes serious diseases like asbestosis, lung cancer, and mesothelioma
• Effects are long-term and often irreversible

Step 2:Evaluate other options.}

• Arsenic Toxic but mainly affects water/soil
• Benzene Harmful but less hazardous than asbestos fibers in air
• Potassium chloride Not a toxic air pollutant

Final Answer:

Concept: Combustion of fuels produces several gaseous pollutants depending on fuel composition and conditions. Step 1:Identify pollutants from combustion.}

• Carbon dioxide Produced from burning carbon fuels
• Nitrogen dioxide Formed at high temperatures
• Sulphur dioxide From sulphur-containing fuels

Step 2:Check ammonia.
Ammonia is mainly released from:

• Agricultural activities
• Decomposition of organic matter

It is not produced by combustion. Final Answer: