Experiment 6: Comparative Reaction of Group III Cations (Ammonium Sulfide)IonsNH4OHexcess NH4OHNH4Cl & NH4OH(NH4)2SNaOHexcess NaOHNa2OH2or H2O2

Al3+Al(OH)3white gelatinous pptinsolubleAl(OH)3white gelatinous pptAl(OH)3white gelatinous pptAl(OH)3white gelatinous pptNaAlO2sol.colorless solnNo reaction

Cr3+Cr(OH)3grayish greenpptinsolubleCr(OH)3grayish greenpptCr(OH)3grayish greenpptCr(OH)3grayish greenpptNaCrO2sol.colorless solnNa2CrO2yellowsoln

Zn2+Zn(OH)2white pptZn(NH3)42+sol. colorless solnsolubleZnSwhite metallic pptZn(OH)2white pptNa2ZnO2 sol.colorless solnNo reaction

Mn2+Mn(OH)2Mn02H2Owhitelight brownpptinsolublesolubleMnSfleshorsalmonpptMn(OH)2whitelight brownpptinsolubleMn02H2Obrownppt

Fe3+Fe(OH)3reddish brownpptinsolubleFe(OH)3reddish brownpptFeSblack pptFe(OH)3reddish brownpptinsolubleNo reaction

Fe2+Fe(OH)2whitegreenreddish brownpptinsolublesolubleFeSblack pptFe(OH)2whitegreenreddish brownpptinsolubleFe(OH)3reddish brownppt

Co2+Co(OH)NO3bluebasic saltCo(NH3)42+dirty yellowsolnsolubleCoSblack pptCo(OH)2bluepptpinkon warminginsolubleCo(OH)3brown or black ppt

Ni2+Ni(OH)NO3greenbasic saltNi(NH3)42+bluesolnsolubleNiSblack pptNi(OH)2apple greenpptinsolubleNi(OH)3apple greenppt with H2O2no oxidation with Na2O2

Experiment 6: Confirmatory Test of Group III Cations (Ammonium Sulfide)IonsReagentsFormulaColor & Nature

Al3+a.) Aluminum TestNH4OH aluminumAl(OH)3white gelatinous pptredlake with aluminum

b.) Thenards blue testNH4OH, Co(No3)2Co(AlO2)3blueash

Cr3+NaOH, H2O2or Na2O2Na2Cro4yellowsoln

a.) AgNo3Ag2Cro4brownish redppt

b.) BaCl2BaCro4yellowppt

c.) (CH3COO)2Pb, HAcPbCro4yellowppt

d.) 3% H2O2conc. H2SO4ether vanishing bluetestbluecolor

Zn2+a.) K4Fe(CN)6Zn2Fe(CN)6or K2Zn3[Fe(CN)6]2white ppt

b.) Rinmmans green testCo(NO3)2, NH4OHCoZnO2greenash

Mn2+HNO2, NaBiO3HMnO4purplesoln

Fe3+a.) KSCNFe(SCN)2+blood redsoln

b.) K4Fe(CN)6Fe4[Fe(CN)6]3prussian blue/blueppt

c.) K2Fe(CN)6FeFe(CN)6or Fe(CN)3brownsoln

Fe2+a.) KSCN-No reaction

b.) K4Fe(CN)6Fe2Fe(CN)6whiteblueppt

c.) K3Fe(CN)6Fe3[Fe(CN)6]2turnbulls blue/blueppt

Co2+KNO2, HAcK2Co(NO2)6yellowppt

Ni2+NH4OH, C4H2N2O2C8H14O4N4Ni or (C4H7O2N2)2Nicherry redppt