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Solubility products. AgCl ( s ) ⇄ Ag + ( aq ) + Cl - ( aq ). Solubility products. Ca(OH) 2 (s) Ca 2+ ( aq ) + 2OH - ( aq ). K sp = [ Ca 2+ ][ OH - ] 2. Ag 2 CrO 4 (s) 2Ag + ( aq ) + CrO 4 2- ( aq ). K sp = [ Ag + ] 2 [ CrO 4 2 - ]. Solubility or precipitation.
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Solubility products AgCl(s) ⇄ Ag+(aq) + Cl-(aq). http:\\asadipour.kmu.ac.ir.....22 slides
Solubility products Ca(OH)2(s) Ca2+(aq) + 2OH-(aq) Ksp = [Ca2+][OH-]2 Ag2CrO4(s) 2Ag+(aq) + CrO42-(aq) Ksp = [Ag+]2[CrO42-] http:\\asadipour.kmu.ac.ir.....22 slides
Solubility or precipitation • AgCl(s) ⇄ Ag+(aq) + Cl-(aq). • Q sp =[Ag+]×[Cl-] • Q sp < K sp More solubility • Q sp = K sp Saturation • Q sp > K sp precipitation http:\\asadipour.kmu.ac.ir.....22 slides
Solubility & Solubility products CaF2(s) ⇄ Ca+2(aq) + 2F-(aq) Ksp = 4.0 × 10-11 x = 2.2 × 10-4 M 0.017 g CaF2/liter. http:\\asadipour.kmu.ac.ir.....22 slides
Common ion effect & solubility Solubility of AgCl in H2O AgCl(s) ⇄ Ag+(aq) + Cl-(aq). Ksp=1.8 × 10-10 x= 1.3 ×10-5 http:\\asadipour.kmu.ac.ir.....22 slides
Common ion effect & solubility Solubility of AgCl in NaCl(0.1M) AgCl(s) ⇄ Ag+(aq) + Cl-(aq). X X+0.1 x = 1.8 × 10-9<<1.3 × 10-5. http:\\asadipour.kmu.ac.ir.....22 slides
Common ion effect & solubility x = 1.8 × 10-90.1M NaCl<<1.3 × 10-5H2O Solubility of AgCl in NaCl(M) AgCl(s) ⇄ Ag+(aq) + Cl-(aq). Soluble [Ag(Cl)2]- More Conc http:\\asadipour.kmu.ac.ir.....22 slides
Salt effect & solubility Solubility of AgCl in NaNO3 AgCl(s) ⇄ Ag+(aq) + Cl-(aq). NO3-- AgCl(s) ⇄ Ag+ + Cl- Na+ http:\\asadipour.kmu.ac.ir.....22 slides
What Concentration of Ag+ is needed for precipitation of Ag2CrO4 in 0.001M solution of CrO42-? Ag2CrO4(s) 2Ag+ + CrO42- KSP = [Ag+]2[CrO42-] = 1.1 x 10-12 [CrO42-] = 0.00100 M [Ag+]2 = 1.1 x 10-12 / 0.00100 = 1.1 x 10-9 [Ag+] >3.3 x 10-5 M http:\\asadipour.kmu.ac.ir.....22 slides
Solubility & pH • If Anion=weak base • Cation=weak acid • CaF2Ca2+ +2F- • AgClCl- + Ag+ • H+ • HF • OH- AgOH http:\\asadipour.kmu.ac.ir.....22 slides
Solubility & pH • What Conc. Of NH4+ is necessary to prevent the formation of Mg(OH)2 precipitate in a sol. of 0.050M in Mg2+ & 0.050M in NH3. Ksp Mg(OH)2=8.9×10-12, • Kb NH3=1.8×10-5. • [NH4]+>6.9 ×10-2M http:\\asadipour.kmu.ac.ir.....22 slides
Precipitation of sulfides • Pb2+ +H2S Pb(HS)2 PbS(s) + H2S • PbS(s) Pb2++ S2- Ksp=7.0× 10-29 • H2S(s) 2H+ + S2-Ksp=1.1× 10-22 constant Fix HCl http:\\asadipour.kmu.ac.ir.....22 slides
Precipitation of sulfides • What must be the H+ Conc. Of a Sol. That is 0.050M in Ni2+ to prevent the precipitation of NiS when the sol. Is saturated with H2S. • KspNiS=3×10-21 • [H+]> 0.04 M http:\\asadipour.kmu.ac.ir.....22 slides
Precipitation of sulfides • A sol. That is 0.050M in Cd2+ and 0.10M in H+ is saturated with H2S.What Conc. Of Cd2+ remains in sol. After CdS has precipitated. KspCdS=1.0×10-28 . • [Cd2+]= CdS=3.6×10-8. http:\\asadipour.kmu.ac.ir.....22 slides
Equilibria involving complex ions • Zn2+ + 6H2O [Zn(H2O)6]2+ • Ligand=complexor • Coordination No. • Chelate • Ks =Kf=1/Kins=1/Kd http:\\asadipour.kmu.ac.ir.....22 slides
Equilibria involving complex ions • What is the Sol. Of AgCl in 0.1M NH3 ? • KspAgCl=1.7×10-9 • Kins [Ag(NH3)2]+ =6.0×10-8 • S=4.8×10-3 http:\\asadipour.kmu.ac.ir.....22 slides
Equilibria involving complex ions • A 0.010M Sol. Of AgNo3 is made in 0.50M NH3 and The complex [Ag(NH3)2]+ forms. 1) What is the Conc. Of Ag+ in the solution? 2) What percentage of total Conc. Of silver is in the form of Ag+ ? 1)[Ag+]=2.6×10-9 2)2.6×10-5% http:\\asadipour.kmu.ac.ir.....22 slides
Complex Ions with S2- • CuS + S2-××× • AS2S3 + S2- 2[AsS3]3- • Al3+ + …..NH3 Al(OH)3(s) • Zn2+ +…..NH3 [Zn(NH3)4]2+ http:\\asadipour.kmu.ac.ir.....22 slides
Amphoterism • Mg2+ +…..OH- Mg(OH)2(s) • Zn2+ + …...OH- [Zn(OH)4]2- http:\\asadipour.kmu.ac.ir.....22 slides