Chapter FifteenPrentice-Hall ©2002Slide 1 of our slides

Chapter FifteenPrentice-Hall ©2002Slide 2 of our slides 2 Ionic equilibriums(2) (Mark=1)

Chapter FifteenPrentice-Hall ©2002Slide 3 of 31 Solubility products AgCl(s) ⇄ Ag + (aq) + Cl - (aq) our slides

Chapter FifteenPrentice-Hall ©2002Slide 4 of our slides 4 Ionic equilibriums(2) (Mark=1)

Chapter FifteenPrentice-Hall ©2002Slide 5 of 31 Mg(OH) 2 (s)  Mg 2+ (aq) + 2OH - (aq) K sp = [Mg 2+ ][OH - ] 2 Ag 2 CrO 4 (s)  2Ag + (aq) + CrO 4 2- (aq) K sp = [Ag + ] 2 [CrO ] Solubility products our slides

Chapter FifteenPrentice-Hall ©2002Slide 6 of 31 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 our slides

Chapter FifteenPrentice-Hall ©2002Slide 7 of 31 Solubility & Solubility products -x+x+2x PbF 2 (s)Pb 2+ (aq) + 2 F – (aq) K sp = [Pb 2+ ] [F – ] 2 = 3.7 x 10 –8 M 3 = (x) (2x) 2 = 3.7 x 10 –8 M 3 = 4x 3 = 3.7 x 10 –8 M 3 x = 2.1 x 10 –3 M our slides K sp = [Pb 2+ ][F - ] 2

Chapter FifteenPrentice-Hall ©2002Slide 8 of 31 Solubility & Solubility products CaF 2 (s) ⇄ Ca +2 (aq) + 2F - (aq) K sp = 4.0 × x = 2.2 × M g CaF 2 /liter our slides K sp = [Ca 2+ ][F - ] 2

Chapter FifteenPrentice-Hall ©2002Slide 9 of 31 Common ion effect & solubility K sp =1.8 × x = 1.3 × Solubility of AgCl in H 2 O AgCl(s) ⇄ Ag+(aq) + Cl-(aq) our slides

Chapter FifteenPrentice-Hall ©2002Slide 10 of 31 Common ion effect & solubility x = 1.8 × << 1.3 × Solubility of AgCl in NaCl(0.1M) AgCl(s) ⇄ Ag+(aq) + Cl-(aq). XX our slides

Chapter FifteenPrentice-Hall ©2002Slide 11 of 31 Common ion effect & solubility H2Ox = 1.8 × M NaCl<< 1.3 × H2O Solubility of AgCl in NaCl(  M) AgCl(s) ⇄ Ag+(aq) + Cl-(aq). Soluble [Ag(Cl) 2 ] - More Conc our slides

Chapter FifteenPrentice-Hall ©2002Slide 12 of 31 Salt effect & solubility Solubility of AgCl in NaNO 3 AgCl(s) ⇄ Ag+(aq) + Cl-(aq). AgCl(s) ⇄ Ag + + Cl our slides

Chapter FifteenPrentice-Hall ©2002Slide 13 of 31 What Concentration of Ag+ is needed for precipitation of Ag 2 CrO 4 in 0.01M solution of CrO 4 2- ? Ag 2 CrO 4 (s)  2Ag + + CrO 4 2- K SP = [Ag + ] 2 [CrO 4 2- ] = 1.0 x [CrO 4 2- ] = 0.01 M [Ag + ] 2 = 1.0 x / 0.01 = 1.0 x [Ag + ] >1.0 x M our slides

Chapter FifteenPrentice-Hall ©2002Slide 14 of 31 Solubility & pH If Anion=weak base Cation=weak acid CaF 2  Ca 2+ +2F - AgCl  Cl - + Ag + H + HF OH - AgOH our slides

Chapter FifteenPrentice-Hall ©2002Slide 15 of 31 Solubility & pH What Conc. Of NH 4 + is necessary to prevent the formation of Mg(OH) 2 precipitate in a sol. of 0.050M in Mg 2+ & 0.050M in NH 3. K sp Mg(OH) 2 =8.9×10 -12, K b NH 3 =1.8× [NH 4 ] + > 6.9 ×10 -2 M our slides

Chapter FifteenPrentice-Hall ©2002Slide 16 of 31 Precipitation of sulfides Pb 2+ +H 2 S  Pb(HS) 2  PbS (s) + H 2 S NiS (s)  Ni 2+ + S 2- K sp =3.0× PbS (s)  Pb 2+ + S 2- K sp =7.0× Pb 2+ + S 2-  PbS (s) H 2 S (s)  2H + + S 2- K sp =1.1× Fix constan t HCl our slides

Chapter FifteenPrentice-Hall ©2002Slide 17 of 31 Precipitation of sulfides What must be the H + Conc. Of a Sol. That is 0.10M in Ni 2+ to prevent the precipitation of NiS when the sol. is saturated with H 2 S. K sp NiS=1.0× H 2 S (s)  2H + + S 2- K sp =1.0× [H + ] > 0.10 M our slides

Chapter FifteenPrentice-Hall ©2002Slide 18 of 31 Precipitation of sulfides A sol. That is 0.025M in Cd 2+ and 0.050M in H + is saturated with H 2 S.What Conc. Of Cd 2+ remains in sol. After CdS has precipitated. K sp CdS=1.0× H 2 S (s)  2H + + S 2- K sp =1.0× [Cd 2+ ]= CdS=1.0× our slides

Chapter FifteenPrentice-Hall ©2002Slide 19 of 31 Equilibria involving complex ions Ligand=complexor Coordination No. Chelate Zn H 2 O [Zn(H2O) 6 ] 2+ K s =K f =1/K ins =1/K d our slides

Chapter FifteenPrentice-Hall ©2002Slide 20 of 31 Equilibria involving complex ions What is the Sol. Of AgCl in 0.1M NH 3 ? K sp AgCl=1.0× K ins [Ag(NH 3 ) 2 ] + =1.0×10 -8 S= our slides

Chapter FifteenPrentice-Hall ©2002Slide 21 of our slides

Chapter FifteenPrentice-Hall ©2002Slide 22 of 31 Equilibria involving complex ions A 0.010M Sol. Of AgNo 3 is made in 0.50M NH 3 and The complex [Ag(NH 3 ) 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× )2.6×10 -5 % our slides

Chapter FifteenPrentice-Hall ©2002Slide 23 of 31 Complex Ions with S 2- CuS + S 2-  ××× AS 2 S 3 + S 2-  2[AsS 3 ] 3- Al 3+ + …..NH 3  Al(OH) 3(s) Zn 2+ +…..NH 3  [Zn(NH 3 ) 4 ] our slides

Chapter FifteenPrentice-Hall ©2002Slide 24 of 31 Amphoterism Mg 2+ +…..OH -  Mg(OH) 2(s) Zn 2+ + …...OH -  [Zn(OH) 4 ] our slides