Chemical
Equilibrium
Labs p208
Thymol Blue Equilibrium
Thymol Blue (Yellow Form)   Thymol Blue + H+ (Blue)
Thymol Blue Equilibrium Stresses and Results
Thymol Blue (Yellow Form)   Thymol Blue
+ H+ (Blue)
Stress: Add HCl (H+). Result: Green Colour
Stress: Add more HCl. Results: Yellow Colour
Stress: Add NaOH (OH-) reacts with H+ to form H2O)
Result: Green Colour
4. Stress: Add more NaOH. Results: Blue Colour
1.
2.
3.
Equilibrium Involving Thiocyanatoiron III Ion
Fe(H2O)63+ (Amber) + SCN1-   Fe(SCN)(H2O)52+ (D. Red)
Equilibrium Involving Thiocyanatoiron III Ion
Fe(H2O)63+ (Amber) + SCN1-   Fe(SCN)(H2O)52+ (D. Red)
a)
b)
c)
d)
Add KCl (Fe3+ forms an insoluble ppt [FeCl3] with Cl1-)
Result: Amber Colour
Add Fe(NO3)3 Possible Stresses: Fe+3 and NO3 –
Result: Darker Red
Add KSCN Possible Stresses: K+ and SCNResult: Darker Red
Add NaOH (Fe3+ forms ins. ppt [Fe(OH)3] with OH1-)
Result: First Orange and then Amber Colour
Equilibrium Involving Cobalt II Complexes
Co(H2O)62+ (aq) + 2 Cl1- (aq)   Co(H2O)4Cl2 (aq) + H2O (ℓ)
a)
b)
c)
d)
Add HCl. Result: Purple Colour
Add H2O. Result: Pink Colour
Add Heat.
Result: Purple Colour
Remove Heat (Cool).
Result: Pink Colour
Equilibrium Involving Chromate and Dichromate Ions
Cr2O72- (aq) + 2 OH1(Orange)
(aq)
  2 CrO42- (aq) + H2O (ℓ)
(Yellow)
Equilibrium Involving Chromate and Dichromate Ions
Cr2O72- (aq) + 2 OH1(Orange)
a)
b)
c)
d)
e)
(aq)
  2 CrO42- (aq) + H2O (ℓ)
(Yellow)
Add NaOH. Result: Orange turns Yellow (yellow stays yellow)
Add HCl.
Result: Yellow turns Orange (orange stays orange)
Add K2CrO4 Result: Colour in both is Orange
Add K2Cr2O7 Result: Colour in both is Yellow
Add Ba(NO3)2 (BaCrO4 is insoluble while BaCr2O7 is soluble)
Result: Chr. sol.  Yellow, Dichr. Sol.  Orange
Ba(NO3)2 in beaker
K2CrO4 in graduate
Equilibrium With Copper II Complexes
Cu(H2O)42+ (aq) + 4 NH4+ + 4 OH-   Cu(NH3)42+ (aq) + 4 H2O
(Light Blue)
(Deep Blue)
Equilibrium With Copper II Complexes
Cu(H2O)42+ (aq) + 4 NH4+ + 4 OH-   Cu(NH3)42+ (aq) + 4 H2O
(Light Blue)
(Deep Blue)
a)
Add NH3 (aq) (NH3 (aq) is NH4+ + OH-)
Result: The light blue colour turns a deeper blue
b)
c)
Add more NH+. Result: The colour  Yet Deeper Blue
Add HCl (Yields H+ and Cl-). The deep Blue  Light Blue
End of Lab Results
A
A