What compound is produced when hydrocarbons are burned?

When hydrocarbons are burned, one of the primary products formed is carbon monoxide, especially when combustion is incomplete. When hydrocarbons combust completely in the presence of sufficient oxygen, the ideal products are carbon dioxide and water. However, incomplete combustion—often due to insufficient oxygen—leads to the production of carbon monoxide, a toxic gas that poses significant health risks.

Nitrogen oxides are formed from the reaction of nitrogen in the air at high temperatures, typically in internal combustion engines or during processes at high flame temperatures. Sulfur dioxide is primarily produced from burning fossil fuels that contain sulfur, such as coal or oil. Nitrogen dioxide is a specific type of nitrogen oxide that can also result from combustion at high temperatures, but it is not a direct product from the burning of hydrocarbons themselves.

Carbon monoxide is particularly concerning in terms of environmental and public health, as it can disrupt the transport of oxygen in the bloodstream, leading to serious health issues. Thus, in the context of combustion of hydrocarbons, carbon monoxide is a significant concern, making it the key answer in this scenario.