solubility equilibria Flashcards
what is a saturated solution?
a solution containing maximum amount of solute that can be dissolved in a given amount of solvent at a particular temperature
what is solubility and solubility product?
solubility product is an equilibrium constant (Kp)
where and when does precipitation take place?
ionic product > Ksp
beyond the saturation point, precipitation occurs until ip = Ksp
define solubility
the maximum amount of solute which can dissolve in a given amount of solvent at a particular temperature
define soluble salts
salts that dissociate fully in solution into their constituent ions
define the ionic product
the product of the concentration of the constituent ions in the solution at that instant
explain the common ion effect
the reduced solubility of a salt in a solution that already contains an ion common to that salt
- added salt dissolves and dissociates completely
- conc of common ion increases momentarily
- eqm position of reaction shifts left (le chatelier’s principle)
- precipitation of solution, decrease in common ion conc
- solubility of solution decreases
explain complex ion formation wrt solubility
solubility of a sparingly soluble salt is increased if the reagent added reacts w one of the constituent ions to form a complex ion
define a complex ion
central metal ion linked to one or more surrounding ions/molecules (ligands) by dative covalent bonds
solubility of silver Cl-
add AgNO3 –> white ppt of AgCl
add excess/conc NH3 –> ppl soluble
solubility of silver Br-
add AgNO3 –> pale cream ppt of AgBr
add excess NH3 –> partially soluble ppt
add conc NH3 –> soluble ppt
solubility of silver I-
add AgNO3 –> yellow ppt of AgI
add excess/conc NH3 –> ppl insoluble
explain why silver halides have different solubility in excess NH3 (aq)
AgI: Ksp value very low –> easily exceeded –> added NH3 cannot sufficiently lower [Ag+] until ionic pdt < Ksp –> ionic pdt of AgI does not fall below Ksp –> insoluble
AgCl: Ksp value much higher than AgI –> [Ag+] decreases –> ionic pdt < Ksp –> soluble
AgBr: Ksp in between, Agbr partially soluble
explain the effect of pH on solubility
for sparingly soluble salt containing the CB of a weak acid, the solubility of the salt is increased when a strong acid is added
