PROBLEM SET #13 CHEM 101‐2 Print name:___ANSWERS_____ Stud. No.:______________________ 1 mark each Q1) What is the cation concentration of a saturated solutions of Al(OH)3: ___3.61 x10‐9 M___ Q2) What is the cation concentration of a saturated solutions of Hg2Cl2: ___7.047 x10‐7 M__ Q3) What is the cation concentration of a saturated solutions of Ag2CO3: ___2.571 x10‐4 M___ Q4) What is the anion concentration of a saturated solutions of Al(OH)3: ___1.084 x10‐8 M___ 2 marks each Q5) Assuming that a single drop is 0.05 mL, how many drops of a 0.10 M KI solution must be added to 100 mL of 0.010 M Pb(NO3)2 to just get a precipitate to form? (That is, how many drops of KI are required to just exceed the saturation concentration for PbI2?) _20 drops (19.8 drops) Q6) 1.0 mL aliquot of 0.050M NaCl is added to 50 mL solution of 0.0010M AgNO3 (aq). What percentage of the silver will precipitate? ____98.63%_____ Q7) Should Al(OH)3 precipitate from a solution that is 0.020 M in Al(NO3)3 and 0.010 M in NH3? (Note: Kb = 1.8 x10‐5 for NH3 + H2O ⇄ NH4+ + OH‐; Ksp = 4.6 x10‐33) __1.43 x10‐12__YES__ Q8) Solid AgNO3 (aq) is slowly added to a solution containing 0.010 M NaBr and 0.010 M NaI in
a fractional or selective precipitation experiment. What percentage of iodide will be removed
before the silver bromide starts to precipitate? (A hint: what is the concentration of silver
ions when the solubility limit for silver bromide is exceeded and what concentration of
iodide does this give.)
___99.984%_____
Q9) If a 0.20 mole sample of AgNO3 is dissolved in 0.500 L of 1.0M NaCN, and 0.20 mole of
NaCl is added, what will be the solubility quotient (Qsp) and will precipitation occur?
_8 x10-23 (or 7.14 x10-19)*_NO_
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