DAY 2: Reactants (Color) Na2SO4 (clear) Na2CO3 (clear) NaCH3C OO (clear) NaCl (clear) KMnO4 (violet)
CuSO4 (blue) CuSO4 (blue)
BaCl2 (clear) HCl (clear)
Observations
Predicted Product
Net Ionic Equation
Precipitate formation
BaSO4 NaCl
Ba2+ (aq) + SO42- (aq)
Type of interionic reaction Precipitate
Gas formation
H2CO3 NaCl
BaSo 4 (s) 2 H (aq) + CO32- (aq)
Gas
H2CO3 (s) H+ (aq) + CH3COO
Odor
+
HCl (clear)
Vinegar smell
KNO3 (clear) FeSO4 (orange)
No visible reaction Red -> Iron precipitate
Na+ Cl- K + NO3FeO4 K + MnO4-
Little NH3 (clear) Excess NH3 (clear)
Less cloudy (blue)
Cu(OH)2 2NH4+ SO42-
MnO4- (aq) + 8 H+ (aq) + 5 Fe2+ (aq) Mn2+ (aq) + 4 H2O (l) + 5 Fe3+ (aq) Cu2+ (aq) + 2 OH(aq) Cu(OH)2 (s)
Cloudy (blue)
[Cu(NH 3)4]2+
Cu2+ (aq) + 4 HN3
CH3COOH NaCl
(aq)
CH3COOH (aq) no net ionic equation
Ion formation Redox
→
(aq)
Precipitate
Complex
Cu(NH 3)42+ (aq)
DAY 3: Ba(NO3) 2
(colorles s)
Ba(NO3) 2
(colorles s) Na2SO4 (colorles s) FeCl3 (orange)
Pb(NO3) 2
(colorles
White ppt (Ba SO4) Orange (NR)
Clear (NR)
Na2SO4 (colorless )
FeCl3 (orange)
White ppt (Ba SO4)
Orange (NR)
Light Yellow (Fe(SO4)3) Fe(SO4)3 (Light Yellow)
Milky White (PbSO4)
Glassy String
Pb(NO3) 2
(colorles s) Clear (NR)
Milky White (PbSO4) Glassy String
KSCN (colorles s)
K 2Cr2O7 (orange)
K 2CrO4 (yellowgreen)
Clear (NR)
Milky Yellow (BaCr2O7)
Milky Yellow (BaCrO 4)
Clear (NR)
Clear Yellow
Clear Yellow
Black
Dark Orange w/ppt (Fe2(Cr2O7 )3) Pastel Yellow w/ppt
Dark Orange w/ppt (Fe2(CrO4 )3) Pastel Yellow w/ppt
Clear (Pb(SCN) ) 2
s) KSCN (colorles s) K 2Cr2O7 (orange)
K 2CrO4 (yellowgreen)
Clear (NR)
Clear (NR)
Black
Milky Yellow (BaCr2O7 )
Clear Yellow
Milky Yellow (BaCrO 4)
Clear Yellow
Dark Orange w/ppt (Fe2(Cr2O7 )3) Pastel Yellow w/ppt (PbCrO4)
DAY 4-5: CATI COLO ON R
Zn2+ Al3+ Ba2+ Ni2+
Clear Clear Clear Clear Green Clear Clear Clear Clear Orang e Clear Pink Clear Clear Clear Clear Blue
Ag+ Ca2+ Mg2+ Sr2+ Fe3+ Mn2+ Na+ K + NH4+ Cu2+
NaOH (little: 2 drops) + + + +
NaOH (excess: 3 drops)
(PbCr2O7) Light Orange
Clear (Pb(SCN) ) 2 Pastel Yellow w/ppt (PbCr2O7)
Light Orange
Pastel Yellow w/ppt (PbCrO4)
Light Orange
Clear Yellow
NH3 (excess: 3 drops)
HCl
++++ ++
NH3 (little: 2 drops) + + + +
+++ ++ +-
-
+ + + +
++ ++ ++ ++
+ + + +
+++ ++ ++
+
++
+
+
++
+
H2SO
Light Orange
KSC N
(NH4)2 S
CH3CSN H2
+ -
-
+ + +
+ -
+ -
+ -
+
+ +
+ +
++
-
-
-
+
-
+-
-
-
-
+
+
4
DAY 6: Cation Zn2+ Ba2+ Ni2+ Ca2+ Sr2+ Fe3+ Mn2+ Na+
(PbCrO4) Clear Yellow
Observation White Green (Bluish Green) Green (Pale/Apple Green) Yellow (Brick Red) Crimson Red (Crimson) Yellow (Gold) Violet (Yellowish Green) Yellow (Intense Yellow)
K + NH4+ Cu2+
Violet (Lilac) Green Green (Blue-Green:Halide ; Green:Non-halide)
Cations With color: Cu(blue), Ni(green), Fe(red/orange), Mn(brown) ++: Ba, Ca, Mg, Sr +-: Zn, Ag, Al -: K, Na, NH 4 => verify through flame test
DAY 10: Solutions
Color of Gas
Odor of Gas
Formula of Gas CO 2
Test for Gas Observations Loss of precipitates
Na2CO3 + H2SO4 Na2SO3 + H2SO4
Colorless
Vinegar-like
Colorless
Mabaho
H2SO3
Na2S + H2SO4
Colorless
Rubber-like
H 2S
Na2S2O3 + H2SO4 NaNO2 + H2SO4
Colorless
Gunpowderlike
S2O3
Paper with K 2Cr2O7 turns from orange to light green Faint orange to white Pb(CH3COO)2 Green-ish
Colorless
Water-like
NO 2
Loss of precipitates
+BaCl2
+3M HCl
DAY 11: Solution ( Na2SO4 ( ) Na2SO3 ( ) Na2CO3 ( ) Na3PO4 (
)
+ KMnO 4 ( )
-
+
++
+
+-
Purple
+
+-
Purple
) Na2CrO4 ( ) NaF ( ) Na2Cr2O7 ( ) NaNO2 ( ) Na2S ( ) Na2S2O3 ( )
+ (yellow)
+-
+ (white)
++
+ (orange)
+-
-
-
+
++
+
++
Red
Dark Red
Confirmatory Tests for Cations Ag+: Add 5 drops 3M HCl to 10 drops unknown => Centrifuge and decant => Treat the ppt with separate 2mL portions of hot water (twice), shaking the test tube while the test tube is heated in the water bath. Decant the first 2mL portion of hot water and treat the precipitate with the second 2mL portion of hot water. => Centrifuge and decant => Add 1mL 6M NH 3 to the precipitate and stir, => Add 6M HNO 3 until acidic. White ppt confirms Ag+. Fe3+, Ni2+: Add 5 drops 3M NaOH to 10 drops unknown => Centrifuge and decant. => Add the water to the precipitate and discard the washing. Add enough water to give a total volume of about 1 mL. Stir. => Divide the solution into two equal portions. => (1)Add 3 drops of 1M KSCN. A deep red color confirms the presence of Fe3+. => (2) Add 6M NH3 dropwise until the solution is basic to litmus. Add 5 drops of dimethyglyoxime [(CH 3)2C2(NOH)2] solution and stir. Formation of a bright red precipitate confirms the presence of Ni2+. Zn2+: (1)Add 5 drops 3M NaOH to 10 drops unknown. Centrifuge and decant. To the hydroxide of zinc, acid 6M NH 3 drop by drop with stirring until it dissolves. Then add 2 drops of thioacetamide solution. Stir and heat in water bath for 3 minutes. Formation of a white precipitate, which dissolves, when the solution is acidified, confirms the presence of Zn2+. (2)To a fresh sample of unknown solution, add 10 drops of thioacetamide solution, stir and heat in the water bath for 3 minutes. Formation of white precipitate, which dissolves when the solution is acidified with 6M HCl, confirms the presence of Zn2+. Cu2+: Add concentrated NH 3 dropwise to the unknown solution until the
solution is distinctly basic. A deep blue solution confirms the presence of Cu2+.
Ca2+: To the unknown solution, add 6 drops of H 2O and concentrated CH3COOH dropwise. Then add 6 drops of 1M (NH 4)2C2O4 and stir and heat in the water bath. The presence of a white precipitate confirms the presence of Ca2+. Mg2+: To the unknown solution, add 6M NH 3 until basic. Then add a small amount of dibasic ammonium phosphate (NH 4)2HPO4 until Mg2+ precipitate as a white MgNH4HPO4 · 6H2O. If the precipitate dissolves in 6M CH 3COOH, then the unknown contains Mg2+. Al3+: Add 2 drops of aluminon reagent (C 22H23O9N23) to the unknown solution. Add 3-5 drops of 6M NH 3 o make the solution just basic. Mix this and let it stand. A flocculent precipitate colored a characteristic of red by the dye proves the presence of Al3+. If color and precipitate are indefinite, make the solution acid with 3M HCl, then basic with NH 3, to build up the NH 4+ concentration so that the solution becomes less basic. Confirmatory Tests for Anions CO32-, SO32-, PO42-: Add 5 drops of BaCl 2 to 10 drops unknown => Centrifuge and decant => Add 1mL of 3M acetic acid dropwise to the solid. Stir. Add 2 more drops of 3M CH 3COOH. Stir, if bubbles are observed, continue to add 3M CH3COOH until no bubbles are noted. This destroys the CO32- Test for CO2 gas. => Divide the solution into 2 portions => (1) Add: 5 drops of 6M HCl, 5 drops of 0.5M Ba(CH 3COO)2 or Ca(CH3COO)2, 5 drops of 3% H 2O2. Formation of a white precipitate confirms presence of SO32-. => (2) Add: 5 drops of concentrated HNO3, 5 drops of ammonium molybdate solution. Heat in water bath for 1 minute. Formation of yellow precipitate confirms the presence of PO43-. SO42-, CrO42-: Add 5 drops of BaCl 2 to 10 drops unknown => Centrifuge and decant => Wash precipitate with 1mL water. Discard washings. Add 10 drops of 3M HCl and stir. If soluble proceed to (2). If not, proceed to (1) => (1) Add BaSO4. Add 10 drops of H 2O and 5 drops concentrated HCl and stir. White precipitate confirms SO42-. => (2) If soluble, BaCrO4. Add 6M NH 3. Yellow precipitate confirms CrO42-. Cl-, Br-, I-, CNS-: Add 5 drops AgNO 3 to 10 drops unknown => Centrifuge and decant => AgCl (White/Dirty White), AgBr (Cream/Light Yellow), AgI (Yellow), AgCNS(White) => Add 2-6 drops 6M NH 3. If soluble, add 3M HNO 3. Stir until the solution is acidic (Check with litmus paper). Formation of white precipitate confirms the presence of Cl-. If insoluble proceed to next step => Divide precipitate into two. => (1) Place a very small amount of solid on a watch glass. Add 2 drops of 3M HCl and 1 drop of FeCl 3. A red-blood solution
confirms the presence of CNS-. => (2) Add 1mL of H2O to the bulk of the residue. Acidify with 6M CH 3COOH. Add 1 microspatula of Zn dust and stir thoroughly for 3 mins. Centrifuge. => Disregard residue. Divide solution into two portions. => Test with litmus paper if solution is acidic. If not, acidify with a few drops of 6M CH 3COOH. Add 10 drops of oil and a few crystals of NaNO 2. Dilute with H 2O to a volume of 2mL and shake vigorously. Did solution turn violet? If yes, I- is present. If no, proceed to next step. => Yellowish color in oil layer confirms the presence of Br-.
NO3-: (1) Place 1 drop of unknown in spot plate. Add 2 drops of concentrated H2SO4 and 1 drop of napthylamine. Wait several minutes. Development of purple color confirms the presence of NO3-. (2) Place 5-10 drops of unknown solution in a small teest tube. Without shaking the test tube, add 5 drops of freshly prepared solution of FeSO 4 and 2-3 drops concentrated H 2SO4. Observe the formation of brown ring at the junction of the solution. This indicates the presence of NO3-. (3) Place a small crystal of FeSO 4 in a depression of a spot plate. Add 1 drop of unknown and 1 drop of concentrated H 2SO4. Formation of a brown ring around the crystal indicates the presence of NO3-. NO2-: (1) Add 1 micro spatula of urea to 1mL 3M HCl. Place 10 drops of this solution to 10 drops of unknown. Evolution of gas confirms the presence of NO2-. (2) Add a freshly prepared solution of FeSO 4 to 5 drops unknown. Then, add 2 drops of concentrated H 2SO4. The rapid evolution of a brown gas confirms the presence of NO2-. CH3COO-: Warm 50mg of the unknown with 2 drops ethanol and 2 drops of sulfuric acid. The fruity odor of the product is apparent if the mixture is allowed to cool and then diluted with water on a watch glass. CrO42-, Cr2O72-: acidify 10 drops unknown solution with concentrated sulfuric acid. Cool. Get 2 drops of this solution and mix to a solution of 1 drop 20% H2O2 and 5 drops ether. Shake. Blue color in the upper ethereal layer confirms the presence of CrO42- if the original solution is yellow, and Cr2O72—if the original unknown solution is orange. C2O42-, F-: acidify 10 drops of unknown solution with 3M CH 3COOH. Boil. Add 10 drops of CaCl 2 solution. If precipitate forms, centrifuge. Wash the precipitate with hot water. Add 5 drops of 1M H 2SO4 and heat. White residue confirms the presence of F-. Centrifuge and decant. Add 1 drop of dilute KMnO4 to the liquid. Decolorization of KMnO 4 confirms the presence of C2O42-. S2-, SO32-, PO43-: Add 5 drops of AgNO 3 to 10 drops of unknown. => S2-(dark brown precipitate), SO32-(white precipitate), PO43-(yellow precipitate).
