Final answer:
Haloalkanes, or alkyl halides, are compounds created by substituting a hydrogen atom of an alkane with a halogen atom.
Step-by-step explanation:
Compounds in which one hydrogen atom of an alkane is substituted by one halogen atom are called haloalkanes (also known as alkyl halides or halogenoalkanes).
These compounds are formed by replacing a hydrogen atom in a hydrocarbon with a halogen atom such as fluorine, chlorine, bromine, or iodine, leading to the general formula R-X, where R represents the rest of the alkane molecule and X represents the halogen. Haloalkanes were once commonly used in applications such as refrigerants and propellants but their use has declined due to environmental concerns.