Chemical Equilibrium

Labs p208

Thymol Blue Equilibrium

Thymol Blue (Yellow Form)Thymol Blue (Yellow Form) Thymol Blue + H+ (Blue)

Thymol Blue Equilibrium Stresses and Results

Thymol Blue (Yellow Form)Thymol Blue (Yellow Form) Thymol Blue + H+ (Blue)

1. Stress: Add HCl (H+). Result: Green ColourGreen Colour

2. Stress: Add more HCl. Results: Yellow ColourYellow Colour

3. Stress: Add NaOH (OH-) reacts with H+ to form H2O)

Result: Green ColourGreen Colour

4. Stress: Add more NaOH. Results: Blue ColourBlue Colour

Equilibrium Involving Thiocyanatoiron III Ion

Fe(H2O)63+ (AmberAmber) + SCN1- Fe(SCN)(H2O)5

2+ (D. Red)

Equilibrium Involving Thiocyanatoiron III Ion

Fe(H2O)63+ (AmberAmber) + SCN1- Fe(SCN)(H2O)5

2+ (D. Red)

a) Add KCl (Fe3+ forms an insoluble ppt [FeCl3] with Cl1-)

Result: Amber Colour Amber Colour

b) Add Fe(NO3)3 Possible Stresses: Fe+3 and NO3 –

Result: Darker RedDarker Red

c) Add KSCN Possible Stresses: K+ and SCN-

Result: Darker RedDarker Red

d) Add NaOH (Fe3+ forms ins. ppt [Fe(OH)3] with OH1-)

Result: First OrangeFirst Orange and then Amber ColourAmber Colour

Equilibrium Involving Cobalt II Complexes

Co(HCo(H22O)O)662+2+ (aq) + 2 Cl1- (aq) Co(HCo(H22O)O)44ClCl22 (aq) + H2O (ℓ)

a) Add HCl. Result: Purple Colour Purple Colour

b) Add H2O. Result: Pink ColourPink Colour

c) Add Heat. Result: Purple Colour Purple Colour

d) Remove Heat (Cool). Result: Pink ColourPink Colour

Equilibrium Involving Chromate and Dichromate Ions

CrCr22OO772-2- (aq) + 2 OH1- (aq) 2 CrO2 CrO44

2-2- (aq) + H2O (ℓ)

(Orange)(Orange) (Yellow)(Yellow)

Equilibrium Involving Chromate and Dichromate Ions

CrCr22OO772-2- (aq) + 2 OH1- (aq) 2 CrO2 CrO44

2-2- (aq) + H2O (ℓ)

(Orange)(Orange) (Yellow)(Yellow)

a)a) Add NaOH. Result: Add NaOH. Result: OrangeOrange turns turns YellowYellow (yellow stays yellow) (yellow stays yellow)

b)b) Add HCl. Result: Add HCl. Result: Yellow Yellow turns turns Orange Orange (orange stays orange) (orange stays orange)

c)c) Add KAdd K22CrOCrO4 4 Result: Colour in both is Result: Colour in both is OrangeOrange

d)d) Add KAdd K22CrCr22OO7 7 Result: Colour in both is Result: Colour in both is YellowYellow

e)e) Add Ba(NOAdd Ba(NO33))2 2 (BaCrO(BaCrO44 is insoluble while BaCr is insoluble while BaCr22OO77 is soluble) is soluble)

Result: Chr. sol. Result: Chr. sol. YellowYellow, Dichr. Sol. , Dichr. Sol. OrangeOrange

Ba(NOBa(NO33))2 2 in beakerin beaker

KK22CrOCrO44 in graduate in graduate

Equilibrium With Copper II Complexes

Cu(HCu(H22O)O)442+2+ (aq) + 4 NH4

+ + 4 OH- Cu(NH3)42+ (aq) + 4 H2O

(Light Blue)(Light Blue) (Deep Blue)

Equilibrium With Copper II Complexes

Cu(HCu(H22O)O)442+2+ (aq) + 4 NH4

+ + 4 OH- Cu(NH3)42+ (aq) + 4 H2O

(Light Blue)(Light Blue) (Deep Blue)

a) Add NH3 (aq) (NH3 (aq) is NH4+ + OH-)

Result: The light blue colour turns a deeper blue

b) Add more NH+. Result: The colour Yet Deeper BlueYet Deeper Blue

c) Add HCl (Yields H+ and Cl-). The deep Bluedeep Blue Light BlueLight Blue

End of Lab Results

A

A