17.4.3 Solubility and the Common Ion Effect Flashcards
Solubility and the Common Ion Effect
- The common ion effect is illustrated by the decrease in solubility of sparingly soluble salts in solutions that contain one of the component ions already in solution.
- The solubility of calcium fluoride (CaF 2 ) in a sodium fluoride (NaF) solution illustrates the common ion effect in 1:2 stoichiometries.
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- The common ion effect is illustrated by the decrease in solubility of sparingly soluble salts in solutions that contain one of the component ions already in solution.
- The example shows the calculation of the solubility of copper(I) bromide (CuBr) in a 0.10 M solution of
hydrobromic acid (HBr). The bromide in solution comes from the HBr (0.10 M) and from CuBr (s). This concentration of bromide is substituted into the equation for the solubility constant for CuBr. To simplify it is assumed that S is much smaller than 0.10. The solution of the equation shows the solubility of bromide is much smaller than it would be in pure water. - The solubility of calcium fluoride (CaF 2 ) in a sodium fluoride (NaF) solution illustrates the common ion effect in 1:2 stoichiometries.
- The example calculates the solubility of calcium fluoride in a 0.10 M solution of sodium fluoride. The contribution of fluoride ion from calcium fluoride (the unknown) is set to 2S to account for the 1:2 stoichiometry. The assumption is made that S is very small, making the calculation easier.
- As expected from Le Châtelier’s principle, the solubility of calcium fluoride is much lower in the presence of the common ion than in pure water.
Which statement about the solubility product, Ksp, is not correct?
Ksp applies to both saturated and unsaturated solutions.
What is the solubility of silver chloride in pure water and in a solution that contains 0.12 M NaCl? The Ksp of AgCl is 1.70 × 10^−10. The dissociation reaction for AgCl is
1.3 × 10^−5; 1.4 × 10^−9
The common ion effect involves the solubility of sparingly soluble salts in a solution that already contains one of the component ions of the sparingly soluble salt.
where Ksp = 4.2 × 10^−8.
The copper bromide is placed in a solution that contains 0.10 M HBr (strong) acid dissolved in aqueous solution. Which statement about this overall reaction is not true?
HBr is the sparingly soluble salt
Calcium phosphate, Ca3(PO4 )2(s), dissolves by the following reaction:
Which of the following shows the correct expression for the Ksp for this reaction?
Ksp = [Ca2+ ]3 [PO43− ]2
(where Ksp = 3.9 × 10−11 )
In the given dissociation reaction of calcium fluoride, you can see that the stoichiometric relationship between the reactants is not 1:1. Suppose that the CaF2 is dissolved in a 0.19 M solution of NaF, sodium fluoride. Which statement about this reaction is not true?
Because S ≈ the initial concentration of F −, then Ksp = [Ca2+ ]1 [ F − ]2 = (S) (initial concentration of F − + 2S)2 = (S) (S + 2S)2.
The Ksp of silver iodide, AgI, is 8.3 × 10−17. What is the final iodide ion concentration if AgI is added to a 0.03 M AgNO3 solution whose volume is 1.00 L?
S = [ I − ] = 2.8 × 10−15
The dissociation reaction for CuBr is
What is the solubility of CuBr in a 0.12 M HBr (strong) acid solution? The Ksp for the dissociation of CuBr(s) is 4.2 × 10−8.
3.5 × 10−7
Look at the reaction:
The initial aqueous solution already had a Br− ion in it as a result of adding HBr acid to the initial aqueous solution. Which statement about this circumstance is not correct?
Because the solubility of CuBr in solution is constant, it is not affected by the HBr in solution.
One of the least soluble salts is HgS, mercury sulfide. When it is mixed with water, the salt dissolves enough to yield 1.3 × 10−27 M Hg2+ (aq) and 1.3 × 10−27 M S2− (aq) in solution.
Which statement about this reaction is not correct?
There are two reactant ions involved in this reaction.
