Final answer:
Halogenated hydrocarbons, also known as haloalkanes, are compounds where hydrogen atoms in hydrocarbons are replaced with halogens. Some of these compounds, like CFCs and carbon tetrachloride, have health and environmental risks, leading to their phased-out use under international agreements.
Step-by-step explanation:
Halogenated hydrocarbons are a class of chemical compounds in which hydrogen atoms in a hydrocarbon are replaced with halogen atoms such as fluorine (F), chlorine (Cl), bromine (Br), or iodine (I). These compounds are also known as haloalkanes, alkyl halides, or halogenoalkanes. These agents are used in several applications, including fire extinguishers, refrigerants, and propellants.
However, some halogenated hydrocarbons, such as chlorofluorocarbons (CFCs) and carbon tetrachloride (CCl4), have been found to be harmful to health and the environment. CCl4, for instance, is a suspected carcinogen and can cause severe liver damage. As a result, its use in dry cleaning and as a fire extinguishing agent has been discontinued due to the risks involved.
Due to their impact on the ozone layer and their potential health hazards, the use of certain halogenated hydrocarbons, particularly CFCs, has been phased out under the Montreal Protocol. Newer, less harmful substances, such as hydrofluorocarbons (HFCs), are being used as replacements for these applications.