Q. What are the major biological functions in which chlorine ions participate?

Like sodium cations, chlorine anions actively participate in the regulation of the osmolarity of cells and tissues by avoiding entrance of water into the cell or excessive loss of water from the cell and crossing the cellular membrane. Chlorine anions have a significant role for the base-acid balance of the organism since they participate, beside with bicarbonate anions, in the pH buffer system of the body. A further function of chlorine is in the digestive physiology inside the gastric lumen, hydrochloric acid secreted by stomach cells ionizes itself into hydrogen and chlorine ions lowering the pH of the gastric juice and then permitting the enzymatic digestion to take place.