Based on oxidation number, explain why carbon monoxide (CO) is flammable but carbon dioxide \(\left(\mathrm{CO}_{2}\right)\) is not.

Understanding the concept of oxidation numbers is crucial when studying chemical compounds and their reactivity. An oxidation number is a measure of the degree of oxidation of an atom in a substance. It represents the number of electrons that an atom either gains or loses when it forms a compound. In a neutral compound, the sum of the oxidation numbers of all atoms must be zero.

For instance, in carbon monoxide (CO), each oxygen atom typically has an oxidation number of -2. There is one oxygen and one carbon atom in CO, and since the compound is neutral, the carbon must have an oxidation number that balances out the -2 from the oxygen. As a result, carbon has an oxidation number of +2 in CO. Conversely, in carbon dioxide (CO2), with one carbon atom and two oxygen atoms, the total oxidation number from the oxygen atoms is -4 (two atoms each with -2), and this means carbon has an oxidation number of +4 to maintain the charge balance.

Flammability is the property of a substance to ignite easily and burn rapidly. This attribute is associated with chemical reactions involving oxygen, known as combustion. Flammable materials have the potential to oxidize quickly, a process that releases energy in the form of heat and light.

Substances that are already highly oxidized are less prone to further oxidation. For a material to be flammable, it must be able to combine with oxygen at a fast rate, which is often the case for substances with low oxidation numbers. They have the capacity to accept more oxygen, allowing them to burn. On the other hand, materials that have high oxidation numbers usually do not burn because they have reached a higher, more stable state and cannot easily accept additional oxygen.

Carbon monoxide (CO) is a colorless, odorless, and highly toxic gas that consists of one carbon atom and one oxygen atom. It has significant implications in the context of oxidation numbers and flammability. Carbon in CO has an oxidation number of +2, which suggests that it can undergo further oxidation.

In a combustion reaction, CO readily binds with oxygen to form carbon dioxide (CO2), releasing a large amount of energy in the form of heat. This propensity for CO to react with oxygen is why it is classified as a flammable gas. Carbon monoxide is both a hazard and a useful industrial fuel -- its flammability is carefully controlled and exploited in processes like iron smelting.

Carbon dioxide (CO2) is a colorless gas used by plants during photosynthesis and produced by the respiration of animals and combustion of organic compounds. It consists of one carbon atom with an oxidation number of +4, and two oxygen atoms, each with an oxidation number of -2.

The oxidation state of carbon in CO2 indicates that it is already fully oxidized. This means that carbon dioxide is not flammable because it cannot oxidize further to release energy. Instead, CO2 is often used as a fire extinguisher because it does not support combustion, displacing oxygen and helping to smother flames in enclosed spaces.