Final answer:
MgCl2 is classified as a salt, which results from the neutralization reaction between a strong acid (HCl) and a strong base (Mg(OH)2).
Step-by-step explanation:
MgCl2 is best classified as a salt. This classification is based on its formation from the reaction of a strong acid (HCl) and a strong base (Mg(OH)2). In a neutralization reaction, when magnesium hydroxide reacts with hydrochloric acid, the products are water and magnesium chloride, illustrating that MgCl2 is indeed a salt.