Final answer:
Chlorine is the highly reactive, greenish-yellow gas used as a bleach and water disinfectant, and is also a component of table salt.
Step-by-step explanation:
The highly reactive, greenish-yellow gas used as a bleach and water disinfectant is called chlorine. Chlorine is also a component of table salt. Sodium hypochlorite, which is commonly known as bleach, is a dilute solution of chlorine and is used as a disinfectant and bleaching agent.