The question asks for the major component of air. To answer this, we need to recall the approximate composition of Earth's atmosphere.
Correct Option: C) Nitrogen (N2) is the major component of air, making up approximately 78% of the Earth's atmosphere.
The question asks to identify the term for air pollutants released directly from their sources. This requires understanding the classification of air pollutants based on their origin.
Correct Option: C) Primary pollutants — These are substances directly emitted into the atmosphere from a source, such as factories, vehicles, or natural events like volcanic eruptions.
This question tests knowledge about the products of combustion, specifically what happens when fossil fuels burn with insufficient oxygen (incomplete combustion).
Correct Option: A) Carbon monoxide (CO) is produced during the incomplete combustion of fossil fuels due to an insufficient supply of oxygen.
The question asks why carbon monoxide (CO) is toxic to humans. This relates to its interaction with the human circulatory and respiratory systems, specifically with blood components responsible for oxygen transport.
Correct Option: C) It binds with haemoglobin more strongly than oxygen, forming carboxyhaemoglobin. This is the correct explanation for carbon monoxide's toxicity. By forming carboxyhaemoglobin, CO prevents haemoglobin from carrying oxygen, leading to cellular hypoxia and organ damage.
The question asks about the primary causes of acid rain. Acid rain is a form of precipitation with high levels of hydrogen ions (low pH), which is detrimental to the environment. Understanding the chemical reactions involved in its formation is key to identifying the correct pollutants.
D) SO2 and NOx in the atmosphere — Sulfur dioxide (\(\text{SO}_2\)) and nitrogen oxides (\(\text{NO}_x\)) are the primary atmospheric pollutants responsible for acid rain. They react with water vapor and other chemicals in the atmosphere to form sulfuric acid and nitric acid, which then fall to the Earth as acid rain.
The pH scale measures how acidic or basic a substance is. Pure water has a neutral pH of 7.0. However, normal rainwater is slightly acidic due to the dissolution of atmospheric carbon dioxide, forming carbonic acid. We need to identify the pH value that reflects this slight acidity.
D) 5.6 — Normal rainwater is slightly acidic due to dissolved atmospheric carbon dioxide, which forms carbonic acid, lowering its pH to around 5.6.