Final answer:
Mustard (HD), Nitrogen mustard (HN) and Lewisite (L) are examples of alkylating agents, which have been used as chemical warfare agents and are known for their ability to damage cells.
Step-by-step explanation:
Mustard (HD), Nitrogen mustard (HN) and Lewisite (L) are examples of alkylating agents. Alkylating agents are chemicals that can transfer alkyl groups to DNA and other organic molecules. They have been used as chemical warfare agents due to their ability to damage cells, especially in the case of mustard and nitrogen mustard, through the alkylation of DNA which prevents it from dividing properly. Lewisite, another type of chemical warfare agent, functions by inhibiting an essential enzyme for cellular respiration, leading to cell death. These substances have been banned under various international laws due to their harmful effects. Chemical warfare has been a subject of concern and regulation particularly due to the use of these and similar compounds during World War I and II.