Which prefix indicates the presence of a carbon chain with a chlorine atom?

The prefix that indicates the presence of a chlorine atom in a carbon compound is "chloro-." In organic chemistry, prefixes are utilized to denote specific substituents attached to the main carbon chain. When a chlorine atom is present as a substituent, the prefix "chloro-" is used in the compound's name to indicate its presence.

For example, in a compound like chloroethane, the "chloro-" prefix signifies that a chlorine atom is attached to the ethane molecule, where there are two carbon atoms. This naming convention is consistent across various organic compounds to identify functional groups and substituents clearly, allowing chemists to communicate the structure of the molecules effectively.