Inorganic Qualitative Analysis

Group I: Mercury, Lead, Silver

MercuLeS

The insoluble chlorides

Group I

6M HCl

precipitant of insoluble chlorides

AgCl = white curdy precipitate

Ag + HCl

PbCl2 = white precipitate

Pb + HCl

Hg2Cl2 = white precipitate

Hg + HCl

Group II: Copper, Cadmium, Bismuth, Lead, Mercuric, Arsenic, Tin, Antimony

Copper-CaBLe MArTiAn

5% thioacetamide in diluted acid

precipitant of Group II

The acid insoluble sulfides

Group II

Copper, Cadmium, Bismuth, Lead

Group II A cations

Group IIA

insoluble in sodium sulfide (Na2S)

Mercuric, Arsenic, Tin, Antimony

Group IIB cations

Group IIB

soluble in sodium sulfide (Na2S)

Group III: Nickel, Cobalt, Zinc, Chromium, Iron, Manganese

NiCo ZaCh Iron Man

5% thioacetamide in ammonia (NH4)

precipitant of group III

The base insoluble sulfides

Group III

Nickel, Cobalt

Group IIIA cations

Group IIIA

soluble in 1M HCl

Group IIIB

insoluble in 1M HCl

Yellow precipitated sulfides

Cd2+

Sn2+ (brown)

As2+

As5+

Orange precipitated sulfides

Sb2+

Sb5+ (red-orange)

White precipitated sulfide

Zn2+

Pink precipitated sulfide

Mn2+

Black precipitated sulfide

Cu2+

Bi3+

Pb2+

Sn4+

Hg2+

Co2+

Ni2+

Ag+

Fe2+

Group IV: Barium, Calcium, Strontium

BaCal St

Ammonium carbonate (NH4)2CO3 + 95% ethanol

precipitant of group IV

The soluble sulfides

The insoluble carbonates

Group IV

All are white precipitates

Group IV precipitates

Group V: Potassium, Lithium, Sodium, Magnesium, Ammonium

PoLiS Magnum Ammo

None

precipitant for group V

The soluble group

Group V

Group V

yield colorless solution for all major identification test reagents

HCl + Ammonium hydroxide

confirmatory reagent for group I

Ag+

white curdy precipitate with HCl, soluble in NH4OH

Pb+2

white precipitate with HCl, insoluble in NH4OH

Potassium ferrocyanide

confirmatory reagent for group II

Brownish red precipitate

copper + potassium ferrocyanide

Yellowish white precipitate

bismuth + potassium ferrocyanide

Dimethylglyoxime (DMG)

confirmatory reagent for group III

Colorless urine

zinc + DMG

Cherry red precipitate

nickel + DMG

Orange solution

cobalt + DMG

Saturated calcium sulfate (CaSO4)

confirmatory reagent for group IV

White precipitate

calcium + saturated CaSO4

Colorless solution

strontium + saturated CaSO4

Diluted NaOH

confirmatory reagent for group 5

Odorless

potassium + diluted NaOH

Pungent odor

ammonium + diluted NaOH

Copper

preliminary examination: blue salts

Ni+2

Ferrous (Fe+2)

Chromic (Cr+3)

Manganates

preliminary examination: green

Chromate

Ferric ion (Fe+3)

preliminary examination: yellow

Dichromate ion

preliminary examination: red-orange

Permanganate

preliminary examination: purple

Mn+2

Cobaltous (Co+2)

preliminary examination: pink

Flame test

an analytical method used for detecting the presence of certain metals where a small amount of a substance is volatilized and the characteristic glow of the substance is observed

Yellow

luminous flame

Blue flame

non luminous flame; where the flame test is conducted

Upper oxidizing zone

Upper reducing zone

Hottest portion of the flame

Lower oxidizing zone

Lower reducing zone

Lower temperature zone

Parts of flame

(Top to bottom)

1/3 height of the flame

hottest portion of the flame; where the flame test is conducted

Na

persistent golden yellow in normal flame test

K

violet (lilac) in normal flame test

Lithium

Carmine red in normal flame test

Strontium

Crimson red in normal flame test

Calcium

brick red in normal flame test

Barium

yellowish green in normal flame test

Borates, Thallium, Copper

green in normal flame test

Lead, Arsenic, Bismuth, Antimony, Copper

blue (wire slowly corroded) in normal flame test

Flame test with cobalt glass

done using platinum wire dipped in conc HCL over non-luminous bunsen flame

the cobalt glass absorbs radiation form Na

Nil

Na in flame test with cobalt glass

Crimson red

K in flame test with cobalt glass

Light green

Ca in flame test with cobalt glass

Purple

Sr in flame test with cobalt glass

Bluish green

Barium in flame test with cobalt glass