Final answer:
Magnesium chloride (MgCl2) when dissolved in water dissociates into Mg2+ and Cl- ions, classifying it as a strong electrolyte. This dissociation is indicative of its ionic nature and its ability to conduct electricity in solution.
Step-by-step explanation:
When magnesium chloride (MgCl2) dissolves in water, it dissociates into its constituent ions - one magnesium ion (Mg2+) and two chloride ions (Cl−). Given the equation:
MgCl2(s) → Mg2+(aq) + 2Cl−(aq)
We can identify that magnesium chloride is an ionic compound that, when dissolved in water, produces ions that can conduct electricity. Thus, MgCl2 is classified as a strong electrolyte because it completely dissociates into ions.
This is supported by the fact that when Mg(s) reacts with Cl2(g), the Mg atom loses electrons to form Mg2+ ions, and the Cl atoms gain electrons to become Cl− ions, resulting in the formation of MgCl2. Furthermore, reactions such as Mg(OH)2 (s) + 2HCl(aq) produce MgCl2 in aqueous form, which again dissociates into ions.
It's important to note that when compounds like MgCl2 form precipitates or when they are involved in acid-base neutralization reactions, their behavior as electrolytes can lead to various chemical phenomena. For example, in the reaction with 2NaOH(aq), magnesium hydroxide, Mg(OH)2, precipitates while sodium chloride, NaCl, remains dissolved.