While naming a haloalkane, the root name must have the name of the longest carbon chain containing the halogen atoms. The type of halogen is given as the prefix (chloro, bromo, iodo). When more than one halogen atom is present attached we use the multiplier in front of the halo prefix( dichloro, trichloro, etc.,)
Therefore when there are two chlorine atoms on the same carbon of methane group, it would be named as dichloromethane.
