Final answer:
When Cl₃ enters the CNS and combines with water, it forms carbonic acid that dissociates and releases H+ ions, which stimulate the central chemoreceptors in the brain to increase the rate and depth of respiration.
Step-by-step explanation:
When Cl₃ enters the central nervous system (CNS) and combines with water, it forms carbonic acid (H₂CO₃). This carbonic acid then dissociates, releasing H+ ions. These H+ ions stimulate the central chemoreceptors, which are specialized receptors in the brain and brainstem that detect changes in the concentration of certain substances, such as carbon dioxide or hydrogen ions. The stimulation of the central chemoreceptors then signals the respiratory centers in the brain to increase the rate and depth of respiration.