ANS:C - carbon monoxide

Carbon monoxide (CO) is a colorless, odorless, and tasteless gas composed of one carbon atom and one oxygen atom. It is produced by incomplete combustion of carbon-containing fuels, such as natural gas, coal, gasoline, wood, and biomass. Here are some key points about carbon monoxide:

1. Formation: Carbon monoxide is produced when carbon-containing fuels are burned with insufficient oxygen supply or inadequate mixing of fuel and air. Incomplete combustion leads to the formation of carbon monoxide instead of carbon dioxide (CO2), which is the product of complete combustion.
2. Toxicity: Carbon monoxide is highly toxic to humans and animals. It is often referred to as the "silent killer" because it is odorless and colorless, making it difficult to detect without specialized equipment. Carbon monoxide can bind to hemoglobin in the blood, reducing its ability to transport oxygen, which can lead to hypoxia (oxygen deficiency) and carbon monoxide poisoning.
3. Sources: Common sources of carbon monoxide include vehicle exhaust, poorly maintained or malfunctioning fuel-burning appliances (such as furnaces, water heaters, and stoves), gas-powered generators, and tobacco smoke. It is also produced during industrial processes such as steel production and chemical manufacturing.
4. Health Effects: Inhalation of carbon monoxide can cause a range of health effects, from mild symptoms such as headaches, dizziness, and nausea to more severe symptoms including confusion, unconsciousness, and death. Prolonged exposure to low levels of carbon monoxide can have chronic health effects, including cardiovascular and neurological problems.
5. Detection and Prevention: Carbon monoxide detectors are essential for detecting the presence of carbon monoxide in indoor environments. These detectors sound an alarm when elevated levels of carbon monoxide are detected, providing early warning to occupants. Preventive measures include regular maintenance of fuel-burning appliances, proper ventilation, and avoiding the use of fuel-burning equipment indoors.