# What is the balanced chemical equation that describes the dissociation of the strong base magnesium hydroxide, Mg(OH)2 in water?

Jul 14, 2014

The equation is $\text{Mg(OH)"_2"(s)" ⇌ "Mg"^"2+""(aq)" + "2OH"^"-""(aq)}$.

#### Explanation:

${\text{Mg(OH)}}_{2}$ is a strong base.

$\text{Mg}$ is a Group 2 Metal, so it form $\text{Mg"^"2+}$ ions. Each ion pairs up with two $\text{OH"^"-}$ ions to form the neutral compound, ${\text{Mg(OH)}}_{2}$.

Magnesium hydroxide is "insoluble", so only a small amount it goes into solution. But every bit that goes into solution dissociates into $\text{Mg"^"2+}$ ions and $\text{OH"^"-}$ ions.

There is a dynamic equilibrium between the solid compound and the ions in solution.

$\text{Mg(OH)"_2"(s)" ⇌ "Mg"^"2+""(aq)" + "2OH"^"-""(aq)}$

The $\text{Mg"^"2+}$ ions and the $\text{OH"^"-}$ ions are leaving the surface of the solid at the same rate as they return from the solution to the surface of the solid.

Here's a video showing the process.