Final answer:
The principal food source of chloride is salt. Salt, or sodium chloride (NaCl), provides chloride ions which are necessary for the production of hydrochloric acid in the stomach and for cell membrane transport.
Step-by-step explanation:
The principal food source of chloride is salt. Salt, or sodium chloride (NaCl), provides chloride ions which are necessary for the production of hydrochloric acid in the stomach and for cell membrane transport. Salt is commonly added to processed foods and is abundant in most diets.