Correct Option
The correct option is (a) 1 only.
Explanation
Carbon monoxide (CO) is a colorless, odorless, and tasteless gas that is slightly less dense than air. It is a significant air pollutant primarily associated with the combustion of carbonaceous materials under conditions of limited oxygen supply.
Statement-wise Analysis
- Statement 1 is Correct: Carbon monoxide is produced by the incomplete combustion of carbon-containing fuels such as coal, firewood, petrol, and diesel. This occurs when there is insufficient oxygen available to fully oxidize the carbon into carbon dioxide (CO2).
- Statement 2 is Incorrect: CO is a highly poisonous and toxic gas. It is dangerous precisely because it has no smell or color, making it difficult to detect without instrumentation.
- Statement 3 is Incorrect: Inhalation of carbon monoxide is detrimental, not beneficial, to human health. It binds to hemoglobin in the blood to form a stable complex known as carboxyhemoglobin. This complex is approximately 300 times more stable than the oxygen-hemoglobin complex. The formation of carboxyhemoglobin significantly reduces the oxygen-carrying capacity of the blood, leading to oxygen starvation (hypoxia), which can cause headaches, dizziness, unconsciousness, and death.
Key Takeaway: Carbon monoxide is a toxic pollutant resulting from incomplete combustion. Its toxicity arises from its high affinity for hemoglobin, which inhibits the transport of oxygen in the human body.