How would you use Le Chatelier's principle to predict whether the solubility of #BaF_2# will increase, decrease, or remain the same on addition of each of the following substances?

#HCl#
#KF#
#NaNO_3#
#Ba(NO_3)_2#

Question

#HCl#
#KF#
#NaNO_3#
#Ba(NO_3)_2#

Peyton Adams · Accepted Answer

We examine the solubility equilibrium:

#BaF_2(s) rightleftharpoons Ba^(2+) + 2F^-# Addition of #HCl# would protonate #F^-#, and drive equilibrium to the right, i.e. bring more of the fluoride into solution. Addition of soluble #KF# increases #F^-#, and equilibrium is driven to the left. Adding sodium nitrate ought to have no impact. And, clearly, addition of soluble barium nitrate should drive equilibrium to the left (by increasing #[Ba^(2+)]#), and barium fluoride should precipitate.

Natalie Anton · Answer

undefined Adding a substance to a solution can affect the solubility of BaF₂ by shifting the equilibrium according to Le Chatelier's principle.

1. Addition of a common ion: If a soluble salt containing the Ba²⁺ ion or the F⁻ ion is added, the solubility of BaF₂ will decrease due to the common ion effect.
2. Addition of a complexing agent: If a complexing agent forms a complex with either the Ba²⁺ ion or the F⁻ ion, it will decrease the concentration of these ions in solution, thus increasing the solubility of BaF₂.
3. Addition of an acid: If an acid is added, it will shift the equilibrium to the left, decreasing the solubility of BaF₂.
4. Addition of a base: If a base is added, it will shift the equilibrium to the right, increasing the solubility of BaF₂.

How would you use Le Chatelier's principle to predict whether the solubility of #BaF_2# will increase, decrease, or remain the same on addition of each of the following substances?

#HCl# #KF# #NaNO_3# #Ba(NO_3)_2#

#HCl#
#KF#
#NaNO_3#
#Ba(NO_3)_2#