Minerals with a negative electrical charge are attracted to the H+ ion. These are called acid minerals. Acid minerals include: chlorine (Cl-), sulfur (S-), phosphorus (P-), and they form hydrochloric acid (HCl), sulfuric acid (H2SO4), and phosphoric acid (H3PO4). Minerals with a positive electrical charge are attracted to the negatively charged OH- ion. These are called alkaline minerals. Nutritionally important alkaline minerals include calcium (Ca+), potassium (K+), magnesium (Mg+), and sodium (Na+). To determine if a food is acid or alkaline, it is burned and the ash is mixed with water. If the solution is acid or alkaline then the food is called acid or alkaline. Ash is the mineral content of the food.