Chemistry - Study Mode

[#761] Which of the following in automobile exhaust can cause cancer?
Correct Answer

(D) Polyclinic hydrocarbons

Explanation

Solution: Polycyclic aromatic hydrocarbons (PAHs) are formed during incomplete combustion. Domestic wood burning and road traffic are the major sources of PAHs. Exposure to PAH-containing substances increases the risk of cancer in humans. The carcinogenicity of PAHs is associated with the complexity of the molecule, i.e., increasing number of benzenoid rings, and with metabolic activation to reactive diol epoxide intermediates and their subsequent covalent binding to critical targets in DNA. Quantitative cancer risk estimates of PAHs as air pollutants are very uncertain because of the lack of useful, good-quality data.

[#762] White lung cancer is caused by
Correct Answer

(C) Textiles

Explanation

Solution: Asbestosis, also called white lung, lung disease that is caused by the prolonged inhalation of asbestos fibres.

[#763] Which of the following is a man-made source of air pollution ?
Correct Answer

(A) Automobile exhaust

Explanation

Solution: Automobile exhaust is a man-made source of air pollution.

[#764] Oxide of sulphur present in the atmosphere are washed down by rains to cause :
Correct Answer

(C) Lowering of pH of soil

Explanation

Solution: Option A: Depletion of fossil fuel reserves Oxides of sulfur in the atmosphere do not directly cause the depletion of fossil fuel reserves. Fossil fuel depletion is due to the consumption of natural resources rather than chemical reactions involving atmospheric sulfur oxides. Option B: Eutrophication in lakes Eutrophication in lakes is typically caused by an excess of nutrients like nitrogen and phosphorus rather than sulfur oxides. While sulfur oxides can contribute to water pollution, they are not the primary cause of eutrophication. Option C: Lowering of pH of soil Oxides of sulfur , such as sulfur dioxide (SO₂) and sulfur trioxide (SO₃), can react with water in the atmosphere to form sulfuric acid (H₂SO₄). When these acidic compounds are washed down by rain, they cause acid rain , which lowers the pH of soil. This acidification of soil can harm plant life and alter soil chemistry, making it the correct answer. Option D: Industrial smog formation While sulfur oxides can contribute to air pollution and visibility issues, industrial smog is primarily formed by particulate matter and other pollutants such as nitrogen oxides. Sulfur oxides may contribute to smog, but they are not the main cause of industrial smog formation. Conclusion: The correct answer is Option C: Lowering of pH of soil . Sulfur oxides present in the atmosphere lead to acid rain, which lowers the soil pH, impacting soil health and plant growth.

[#765] Supersonic jet causes pollution by thinning of
Correct Answer

(A) O 3 layer

Explanation

Solution: Most commercial flights are confined to the troposphere, but high-level supersonic aircraft inject pollutants into the stratosphere, which leads to the thinning of the ozone layer. Of these nitrogen oxides are especially harmful.