Questions and Answers
What are sparingly soluble salts?
Salts that dissociate partially in the solution into their constituent ions.
What is the definition of solubility of a salt?
It is the concentration of the salt which refers to the maximum amount of the solute that can be dissolved in 1 dm^3 of solvent to make a saturated solution at a given temperature.
What does saturated solution mean?
It means if I were to dissolve 1 more unit of solute in the water, it cannot dissolve anymore.
What is solubility measured as?
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What is the definition of Ksp?
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What factors affect Ksp?
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How is solubility of a salt denoted?
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What is the definition of the common ion effect?
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What is the standard answer when asked how the addition of another salt with a common ion affects solubility?
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What type of salts are always sparingly soluble?
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What is complex ion formation?
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What is the standard answer for the effect of complex ion formation on the solubility of the salt?
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What is the trend of solubility of silver halides AgCl, AgBr, AgI down group 17?
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What is the observation when Cl- of AgCl is reacted with AgNO3 followed by NH3?
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What is the observation when I- of AgI is reacted with AgNO3 followed by NH3?
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What is the trend of the colors of silver halides AgCl, AgBr, AgI down group 17?
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How is the solubility product (Ksp) of a salt related to its solubility in a solvent?
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What is the definition of ionic product?
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What happens when IP = Ksp?
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What happens when IP < Ksp?
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What happens when IP > Ksp?
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What happens to the concentration when 2 solutions are mixed in equal volumes?
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What are the steps for solving precipitation problems involving sparingly soluble salts?
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Study Notes
Sparingly Soluble Salts
- Sparingly soluble salts only partially dissociate in solution into ions.
- Common examples include carbonates and hydroxides.
Solubility and Saturation
- Solubility of a salt indicates the maximum amount that can dissolve in 1 dm³ of solvent at a given temperature, expressed in mol dm⁻³.
- A saturated solution can't dissolve any more solute; adding any more will not increase concentration.
Equilibrium and Ksp
- Ksp is the equilibrium constant equal to the product of the molar concentrations of dissociated ions in a saturated solution, each raised to the power of their coefficients.
- Ksp remains constant at a constant temperature, making temperature a key factor affecting solubility.
Common Ion Effect
- The presence of a common ion from an external source decreases the solubility of a sparingly soluble salt by shifting equilibrium to the left.
- Le Chatelier's principle explains this shift, resulting in the formation of more solid salt.
Complex Ion Formation
- Adding certain reagents can lead to complex ion formation, which increases the solubility of sparingly soluble salts.
- When complexing agents (e.g., NH3) are introduced, they react with cations to form complex ions, reducing the concentration of the common ion and shifting equilibrium right.
Solubility Trends in Silver Halides
- Solubility decreases from AgCl to AgI as you move down group 17 of the periodic table.
- Color changes from white (AgCl) to cream (AgBr) to yellow (AgI).
Ionic Product (IP) and Ksp Relationship
- The ionic product is determined by the concentration of dissolved ions and varies with solution conditions, unlike Ksp which is constant for a given salt at a specific temperature.
- If IP equals Ksp, the solution reaches saturation without precipitation; if IP is less than Ksp, no precipitation occurs; if IP exceeds Ksp, precipitation starts.
Concentration Changes Upon Mixing Solutions
- When two solutions are mixed in equal volumes, the concentration of solutes is halved due to the doubled total volume.
Steps for Solving Precipitation Problems
- Write the partial dissociation equation for the sparingly soluble salt.
- Derive the ionic product expression for the dissociation.
- Calculate the new ion concentrations based on mixed solutions.
- Substitute these concentrations into the ionic product expression and assess against Ksp to determine precipitation status.
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Description
Test your knowledge on solubility equilibria with this flashcard quiz. Learn about sparingly soluble salts and the definition of solubility in an interactive format. Perfect for reviewing key concepts in chemistry.