Mg(OH)2(aq) <--> Mg2+ (aq) + 2OH-(aq)

a) what would happen to the equilibrium if some acid is added to the soultuion?

b) what would happen to the solubility of Mg(OH)2?

c) what would happen to the Ksp?

Le Chatelier's Principle says that a system at equilibrium (this is at equilibrium) will shift so as to UNDO what we do to it.

So if you add acid, that H^+ combines with the OH^-, that reduces the OH^- (because H2O is formed) and reducing OH^- means the reaction will increase OH (since we took it away) and the only way OH can be increased is for the rxn to move to the right. That will happen. Now you do the other two.

a) If some acid is added to the solution, the equilibrium would say, "Oh no, we have too much acid! Time to balance things out!" And in an attempt to neutralize the acid, the equilibrium would shift to the left, producing more Mg(OH)2 (s) to counteract the increase in acidity.

b) The solubility of Mg(OH)2 might feel a little insecure when acid is added, but don't worry, it won't dissolve into thin air. In fact, the solubility of Mg(OH)2 would decrease because the excess acid would react with the hydroxide ions (OH-) in the solution, forming water and reducing the concentration of hydroxide ions.

c) As the equilibrium shifts to the left, the concentration of Mg2+ ions and OH- ions would decrease, which means that the Ksp (solubility product constant) would also decrease. So, Ksp would become a little less spontaneous, kind of like a shy turtle hiding in its shell.

a) If some acid is added to the solution, it would react with the hydroxide ions (OH-) produced by the dissociation of Mg(OH)2. The acid would neutralize the hydroxide ions by donating hydrogen ions (H+) and forming water molecules. This reaction will shift the equilibrium to the left, towards the reactant side, in order to counteract the decrease in hydroxide ions.

b) Adding acid to the solution would decrease the solubility of Mg(OH)2. This is because the solubility of a sparingly soluble salt is dependent on the concentration of the ions in solution. When acid is added, it reacts with the hydroxide ions, reducing their concentration. As a result, the concentration of the hydroxide ions decreases, leading to a decrease in the solubility of Mg(OH)2.

c) The Ksp (solubility product constant) is a measure of the equilibrium position for the dissolution of a sparingly soluble salt. Adding acid to the solution would shift the equilibrium to the left, decreasing the concentration of the hydroxide ions. Since the Ksp is calculated using the concentrations of the ions in solution, a decrease in hydroxide ion concentration would result in a decrease in the Ksp value for Mg(OH)2.

To answer these questions, let's understand the chemical equation and the concept of equilibrium in a chemical reaction.

In the given equation: Mg(OH)2(aq) ⇌ Mg2+(aq) + 2OH-(aq), Mg(OH)2 dissolves in water to produce Mg2+ ions and OH- ions.

a) What would happen to the equilibrium if some acid is added to the solution?

When an acid is added to the solution, it increases the concentration of H+ ions. The added H+ ions react with the OH- ions to form water (H2O), effectively removing the OH- ions from the solution. According to Le Chatelier's principle, when the concentration of one of the reactants (OH-) is reduced, the equilibrium will shift to the right to counteract this change. This means that more Mg(OH)2 will dissolve to produce more OH- ions.

b) What would happen to the solubility of Mg(OH)2?

The solubility of Mg(OH)2 refers to the amount of the compound that can dissolve in a given solvent (usually water) at a particular temperature. When an acid is added, it increases the solubility of Mg(OH)2. As explained above, the increase in H+ concentration causes a shift in equilibrium and promotes the dissolution of more Mg(OH)2, resulting in an increased solubility.

c) What would happen to the Ksp?

The Ksp (solubility product constant) is a measure of the concentration of ions in a solution at which an ionic compound is in a state of equilibrium with its solid form. In this case, the Ksp can be represented as [Mg2+][OH-]^2. When an acid is added, the concentration of OH- ions decreases due to the reaction with H+ ions. As a result, the Ksp will not change significantly since the concentration of Mg2+ ions remains the same. The Ksp value represents the product of ion concentrations based on the stoichiometry of the balanced equation.