Final answer:
MgCl2 is an ionic compound known as a salt, formed by the reaction of a strong base, magnesium hydroxide, with a strong acid, hydrochloric acid.
Step-by-step explanation:
MgCl2 is best classified as a salt. It is an ionic compound formed from the reaction between a strong acid, hydrochloric acid (HCl), and a strong base, magnesium hydroxide (Mg(OH)2). When Mg(OH)2 reacts with HCl, a neutralization reaction occurs, producing magnesium chloride (MgCl2) and water (H2O). Magnesium chloride, MgCl2, is the compound in question and is considered a salt because it is composed of the cation Mg2+ and the anion Cl−.