Dear Student.....HCl is the mineral acid present in our stomach. HCl’s primary function is to maintain a sterile environment and to initiate the conversion of pepsinogen to pepsin. HCI activates the enzyme pepsin, which aids in the digestion of proteins by breaking amino acid bonds, and it breaks up connective tissues and plant cell walls. It also converts ingested ferric ions into ferrous ions, which are used for hemoglobin synthesis. And HCl contributes to disease resistance by destroying most ingested pathogens and bacteria that are on the foods you eat....... Regards