Gen Chem Lab 12

sodium (Na+)

flame test produces bright yellow flame

ammonium (NH4+)

turns red litmus paper blue (basic)

silver (Ag+)

forms white precipitate of AgCl

Iron III (Fe3+)

forms blue precipitate of Fe4[Fe(CN)6]3

aluminum (Al3+)

forms red lake precipitate of Al(OH)3

chromium III (Cr3+)

forms faint yellow precipitate of BaCrO4

calcium (Ca2+)

forms white precipitate of CaC2O4, bright red in flame test

magnesium (Mg2+)

forms blue lake of Mg(OH)2

nickel (Ni2+)

forms red precipitate of Ni(C4H7N2O2)2

zinc (Zn2+)

forms grey-blue solution including Zn3K2[Fe(CN)6]2

NaOH(aq) reagent:

Nh4+(aq) + OH-(aq) → NH3(g) + H2O(l)

NH3(g) + H2O(l) → Nh4+(aq) + OH-(aq)

a gas is formed which turns moist red litmus blue (basic)

HCl(aq) reagent: Ag+(aq) + Cl-(aq) → AgCl(s)

white precipitate forms

NH3(aq) reagent): AgCl(s) + 2NH3(aq) → [Ag(NH3)2]+(aq) + Cl-(aq)

white precipitate dissolves

HNO3(aq) reagent: [Ag(NH3)2]+(aq) + Cl-(aq) + 2H+(aq) → AgCl(s) + 2NH4+(aq)

white precipitate reforms

NH3(aq) and NH4CL(aq) reagent:

Fe3+(aq) + 3NH3(aq) + 3H2O(l) → Fe(OH)3(s) + 3NH4+(aq)

Cr3+(aq) + 3NH3(aq) + 3H2O(l) → Cr(OH)3(s) + 3NH4+(aq)

Al3+(aq) + 3NH3(aq) + 3H2O(l) → Al(OH)3(s) + 3NH4+(aq)

dark precipitate forms

NaOH(aq) and H2O2(aq) reagent: Al(OH)3(s) + OH-(aq) → [Al(OH)4]-(aq)

2Cr(OH)3(s) + 3H2O2(aq) + 4OH-(aq) → 2CrO4 2-(aq) + 8H2O(l)

some precipitate dissolves, decantate is yellow, precipitate is rust-colored

HCl(aq) reagent: Fe(OH)3(s) + 3H+(aq) → Fe3+(aq) + 3H2O(l)

precipitate dissolves

K4[Fe(CN)6](aq) reagent: 4Fe3+(aq) + 3[Fe(CN)6]4-(aq) → Fe4[Fe(CN)6]3(s)

blue precipitate forms

HCl(aq) reagent: 2CrO4 2-(aq) + 2H+(aq) → H2O(l) + Cr2O7-(aq)

[Al(OH)4]-(aq) + 4H+(aq) → Al3+(aq)+ 4H2O(l)

yellow/orange solution forms

NH3(aq) reagent: Al3+(aq) + 3NH3(aq) + 3H2O(l) → Al(OH)3(s) + 3NH4+(aq)

Cr2O7 2-(aq) + 2NH3(aq) + H2O(l) → 2CrO4 2-(aq) + 2NH4+(aq)

precipitate and yellow solution forms

HCl(aq) reagent: Al(OH)3(s) + 3H+(aq) → Al3+(aq) + 3H2O(l)

precipitate dissolves

aluminon and NH3(aq) reagent: Al3+(aq) + 3NH3(aq) + 3H2O(l) + aluminon) → Al(OH)3(s) + 3NH4+(aq)

precipitate reforms to give a red lake

BaCl2(aq) reagent: Ba2+(aq) + C2O4 2-(aq) → BaC2O4(s)

faint yellow precipitate forms

(NH4)2C2O4(aq) reagent: Ca2+(aq) + C2O4 2-(aq) → CaC2O4(s)

precipitate forms

HCl(aq) reagent:CaC2O4(s) + 2H+(aq) → Ca2+(aq) + H2C2O4(aq)

precipitate dissolves, brick-red in flame test

HNO3(aq) reagent and heat:

H2O(l) → H2O(g)

NH4Cl(s) → NH3(g) + HCl(g)

NH4NO3(s) → N2O(g) + 2H2O(g)

white fumes and light colored residue forms

HCl(aq) reagent + light colored residue

residue dissolves

NaOH(aq) reagent:

Ni2+(aq)+2OH-(aq) → Ni(OH)2(s)

Mg2+(aq)+2OH-(aq) → Mg(OH)2(s)

Zn2+(aq) + 4OH-(aq) → [Zn(OH)4)]2-(aq)

precipitate forms

K4[Fe(CN)6](aq) and HCl(aq) reagent: 3[Zn(OH)4]2-(aq) + 12H+(aq) + 2K+(aq) + 2[Fe(CN)6]4-(aq) → Zn3K2[Fe(CN)6]2(s) + 12H2O(l)

grey-blue precipitate forms

NH3(aq) reagent: Ni(OH)2(s) + 6NH3(aq) → [Ni(NH3)6]2+(aq) + 2OH-(aq)

pale violet decantate forms

dimethylgloxime reagent: [Ni(NH3)6]2+(aq) + 2HC4H7N2O2(aq) → Ni(c4H7N2O2(s) + 4NH3(aq) + 2NH4+(aq)

red precipitate forms

HCl(aq) reagent: Mg(OH)2(s) + 2H+(aq) → Mg2+(aq) + 2H2O(l)

precipitate dissolves

magensium and NaOH(aq) reagent: Mg2+(aq) + 2OH-(aq) + Mg reagent → Mg(OH)2(s)

blue lake forms