Final answer:
The major products resulting from the sequence of reactions starting with 1,2-dichloroethane are dichloromethane, trichloromethane (chloroform), and ultimately tetrachloromethane (carbon tetrachloride) with the reaction yield depending on the time allowed.
Step-by-step explanation:
The question relates to a sequence of reactions starting with 1,2-dichloroethane. As the reaction proceeds, further substitution happens leading to a series of compounds with increasing numbers of chlorine atoms substituted for hydrogen atoms on the ethane molecule. Initially, dichloromethane would be formed after the first chlorine substitution. As the reaction continues, trichloromethane, commonly known as chloroform, and ultimately tetrachloromethane, also known as carbon tetrachloride, are produced. The mixture of products' relative amounts will depend on the reaction duration. In halogenation reactions like these, chlorofluorocarbons can be synthesized by further reacting chloroalkanes with hydrofluoric acid (HF). The reaction sequence is an example of halogenation where multiple substitution steps can lead to various products based on the conditions.