How can you write a report for CATIONS?
‫ﺷﻜﺮﺧﺎﺹ ﻟﻸﺳﺘﺎﺫﺓ ﻣﻴﻤﻮﻧﺔ ﺍﻟﺮﻳﺎﻧﻲ‬
1. Detection for ammonium
Experiment
Radical name: Ammonium
Chemical symbol of Radical: NH4+
Observation
Result
Solid salt + Na2CO3
Colourless gas is evolved,
The gas is NH3
(solid)+ drops of water
recognized by its odour.
the cation is NH4+
Brown ppt. is formed and with very
The ppt. is iodide of Millonˊs
Salt solution + Nessler's
reagent
Salt solution +
Na3[Co(NO2)6]
dil. solution brown or yellow colour base.
is appeared
the cation is NH4+
Yellow ppt. is formed
The ppt. is (NH4)3[Co(NO2)6]
Colourless gas is evolved,
recognized by its odour, by formed
Salt solution + NaOH
dense white fumes with conc. HCl,
and by turning red litmus paper
The gas is NH3
The white fumes is NH4Cl
blue.
2. Detection for cations in Group I
Experiment
Solid salt + Na2CO3 (solid)
Radical name: Silver
Chemical symbol of Radical: Ag+
Observation
-ve
Result
The cation is not NH4+
+ drops of water
Salt solution + dil. HCl
White ppt. is formed, which
The ppt. is AgCl
dissolves in NH4OH and turns
the cation is Ag+
violet when exposed to light
Salt solution + NaOH
Brown-black ppt. is formed
The ppt. is Ag2O
Salt solution + KI
Yellow ppt. is formed
The ppt. is AgI
Salt solution + K2CrO4
Brick-red ppt. is formed
The ppt. is Ag2CrO4
Experiment
Radical name: Lead
Chemical symbol of Radical: Pb2+
Observation
Solid salt + Na2CO3 +
-ve
Result
The cation is not NH4+
drops of water
Salt solution + dil. HCl
White ppt. is formed, insoluble in
The ppt. is PbCl2
NH4OH but soluble in hot water
the cation is Pb2+
and reprecipitates on cooling
Salt solution + NaOH
White ppt. is formed, soluble in
The ppt. is Pb(OH)2
excess of NaOH
Salt solution + KI
Yellow ppt. is formed, soluble in
The ppt. is PbI2
excess of KI
Salt solution + K2CrO4
Experiment
Solid salt + Na2CO3 (solid)
Yellow ppt. is formed
The ppt. is PbCrO4
Radical name: Mercurous
Chemical symbol of Radical: Hg22+
Observation
-ve
Result
The cation is not NH4+
+ drops of water
Salt solution + dil. HCl
White ppt. is formed, turns to black
The ppt. is Hg2Cl2
when NH4OH is added
the cation is Hg22+
Salt solution + NaOH
Black ppt. is formed
The ppt. is Hg2O
Salt solution + KI
Yellowish-green ppt. is formed,
The ppt. is Hg2I2
soluble in excess of KI and the
solution turns grey
Salt solution + K2CrO4
Brown ppt. is formed, converted to
red crystalline form on boiling
The ppt. is Hg2CrO4
Detection for cations in Group III
Experiment
Radical name: Aluminum
Chemical symbol of Radical: Al3+
Observation
Solid salt + Na2CO3 (solid)
Result
-ve
The cation is not NH4+
-ve
The cation is not from Group
+ drops of water
Salt solution + dil. HCl
I
Salt solution + dil. HCl +
-ve
The cation is not from Group
H2S
II
Salt solution + NH4Cl +
White gelatinous ppt. is formed
The ppt. is Al(OH)3
the cation is Al3+
NH4OH
Salt solution + NaOH
White gelatinous ppt. is formed,
The ppt. is Al(OH)3
soluble in excess of NaOH
Salt solution + Na3PO4
Experiment
White gelatinous ppt. is formed
The ppt. is AlPO4
Radical name: Chromium
Chemical symbol of Radical: Cr3+
Observation
Result
-ve
The cation is not NH4+
Salt solution + dil. HCl
-ve
The cation is not from Group I
Salt solution + dil. HCl +
-ve
The cation is not from Group II
Solid salt + Na2CO3 (solid)
+ drops of water
H2S
Salt solution + NH4Cl +
Grayish-green gelatinous ppt. is
The ppt. is Cr(OH)3
NH4OH
formed
the cation is Cr3+
Salt solution + NaOH
Grayish-green gelatinous ppt. is
The ppt. is Cr(OH)3
formed, soluble in excess of NaOH
Salt solution + Na3PO4
Greenish ppt. is formed
The ppt. is CrPO4
Experiment
Radical name: Ferrous
Chemical symbol of Radical: Fe2+
Observation
Result
-ve
The cation is not NH4+
Salt solution + dil. HCl
-ve
The cation is not from Group I
Salt solution + dil. HCl +
-ve
The cation is not from Group II
Solid salt + Na2CO3 (solid)
+ drops of water
H2S
Salt solution + NH4Cl +
Dirty green ppt. is formed, turns to
The green ppt. is Fe(OH)2
NH4OH
brown ppt. when left in air
The brown ppt. is Fe(OH)3
the cation is Fe2+
Salt solution + NaOH
Dirty green ppt. is formed, turns to
The green ppt. is Fe(OH)2
brown ppt. when left in air
The brown ppt. is Fe(OH)3
Salt solution + K4Fe(CN)6
Pale blue ppt. is formed
The ppt. is K2Fe[Fe(CN)6]
Salt solution + K3Fe(CN)6
Dark blue ppt. is formed
The ppt. is KFe[Fe(CN)6]
Experiment
Radical name: Ferric
Chemical symbol of Radical: Fe3+
Observation
Result
-ve
The cation is not NH4+
Salt solution + dil. HCl
-ve
The cation is not from Group I
Salt solution + dil. HCl +
-ve
The cation is not from Group II
Solid salt + Na2CO3 (solid)
+ drops of water
H2S
Salt solution + NH4Cl +
Reddish-brown gelatinous ppt. is
The ppt. is Fe(OH)3
NH4OH
formed
the cation is Fe3+
Salt solution + NaOH
Reddish-brown ppt. is formed
The ppt. is Fe(OH)3
Salt solution + K4Fe(CN)6
Dark blue ppt. is formed, soluble in
The ppt. is Fe4[Fe(CN)6]3
excess of K4Fe(CN)6
Salt solution + K3Fe(CN)6
Brown colour is appeared
The colour is Fe[Fe(CN)6]
Detection for cations in Group IV
Experiment
Radical name: Zinc
Chemical symbol of Radical: Zn2+
Observation
Result
-ve
The cation is not NH4+
Salt solution + dil. HCl
-ve
The cation is not from Group I
Salt solution + dil. HCl +
-ve
The cation is not from Group II
-ve
The cation is not from Group III
Solid salt + Na2CO3 (solid)
+ drops of water
H2S
Salt solution + NH4Cl +
NH4OH
Salt solution + NH4Cl +
White ppt. is formed
the cation is Zn2+
NH4OH + H2S
Salt solution + NaOH
The ppt. is ZnS
White gelatinous ppt. is formed,
The ppt. is Zn(OH)2
soluble in excess of NaOH
Salt solution + NH4OH
White ppt. is formed, soluble in
The ppt. is Zn(OH)2
excess of NH4OH
Experiment
Radical name: Manganese
Chemical symbol of Radical: Mn2+
Observation
Solid salt + Na2CO3 (solid)
-ve
The cation is not NH4+
Salt solution + dil. HCl
-ve
The cation is not from Group I
Salt solution + dil. HCl +
-ve
The cation is not from Group II
-ve
The cation is not from Group III
Result
+ drops of water
H2S
Salt solution + NH4Cl +
NH4OH
Salt solution + NH4Cl +
Buff ppt. is formed
the cation is Mn2+
NH4OH + H2S
Salt solution + NaOH
Salt solution + NH4OH
The ppt. is MnS
White gelatinous ppt. is formed,
The white ppt. is Mn(OH)2
becomes brown in air
The brown ppt. is Mn(OH)3
White gelatinous ppt. is formed,
The white ppt. is Mn(OH)2
becomes brown in air
The brown ppt. is Mn(OH)3
Experiment
Radical name: Cobalt
Chemical symbol of Radical: Co2+
Observation
Result
-ve
The cation is not NH4+
Salt solution + dil. HCl
-ve
The cation is not from Group I
Salt solution + dil. HCl +
-ve
The cation is not from Group II
-ve
The cation is not from Group III
Solid salt + Na2CO3 (solid)
+ drops of water
H2S
Salt solution + NH4Cl +
NH4OH
Salt solution + NH4Cl +
Black ppt. is formed
the cation may be Co2+ or Ni2+
NH4OH + H2S
Salt solution +
The ppt. may be CoS or NiS
-ve
the cation is Co2+
Dimethylglyoxime
Salt solution + NaOH
Blue ppt. is formed, turns to pink
The ppt. is Co(OH)NO3
with heating in excess of NaOH
Salt solution + NH4OH
Blue ppt. is formed, soluble in
The ppt. is Co(OH)NO3
excess of NH4OH
Experiment
Radical name: Nickel
Chemical symbol of Radical: Ni2+
Observation
Result
-ve
The cation is not NH4+
Salt solution + dil. HCl
-ve
The cation is not from Group I
Salt solution + dil. HCl +
-ve
The cation is not from Group II
-ve
The cation is not from Group III
Solid salt + Na2CO3 (solid)
+ drops of water
H2S
Salt solution + NH4Cl +
NH4OH
Salt solution + NH4Cl +
Black ppt. is formed
the cation may be Co2+ or Ni2+
NH4OH + H2S
Salt solution +
Dimethylglyoxime
The ppt. may be CoS or NiS
Red ppt. is formed
The ppt. is nickel
dimethylglyoxime
the cation is Ni2+
Salt solution + NaOH
Salt solution + NH4OH
Greenish ppt. is formed
The ppt. is Ni(OH)2
Greenish ppt. is formed, soluble in
The ppt. is Ni(OH)2
excess of NH4OH
3. Detection for cations in Group V
Experiment
Radical name: Calcium
Chemical symbol of Radical: Ca2+
Observation
Result
-ve
The cation is not NH4+
Salt solution + dil. HCl
-ve
The cation is not from Group I
Salt solution + dil. HCl +
-ve
The cation is not from Group II
-ve
The cation is not from Group III
-ve
The cation is not from Group IV
Solid salt + Na2CO3 (solid)
+ drops of water
H2S
Salt solution + NH4Cl +
NH4OH
Salt solution + NH4Cl +
NH4OH + H2S
Salt solution + NH4Cl +
White ppt. is formed
NH4OH + (NH4)2CO3
The ppt. may be CaCo3, SrCo3
or BaCO3
the cation may be Ca2+, Sr2+ or
Ba2+
Salt solution + CaSO4
No ppt. is formed
the cation is Ca2+
Salt solution + K2CrO4
From dil. solution: No ppt. is
The ppt. is CaCrO4
formed
From conc. solution: yellow ppt. is
formed, soluble in acetic acid
Flame test
Brick red colour is appeared
the cation is Ca2+
Experiment
Radical name: Strontium
Chemical symbol of Radical: Sr2+
Observation
Result
-ve
The cation is not NH4+
Salt solution + dil. HCl
-ve
The cation is not from Group I
Salt solution + dil. HCl +
-ve
The cation is not from Group II
-ve
The cation is not from Group III
-ve
The cation is not from Group IV
Solid salt + Na2CO3 (solid)
+ drops of water
H2S
Salt solution + NH4Cl +
NH4OH
Salt solution + NH4Cl +
NH4OH + H2S
Salt solution + NH4Cl +
White ppt. is formed
NH4OH + (NH4)2CO3
The ppt. may be CaCo3, SrCo3
or BaCO3
the cation may be Ca2+, Sr2+ or
Ba2+
Salt solution + CaSO4
Salt solution + K2CrO4
White ppt. is formed on heating or
The ppt. is SrSO4
after some time
the cation is Sr2+
Yellow ppt. is formed, soluble in
The ppt. is SrCrO4
acetic acid
Flame test
Crimson red colour is appeared
the cation is Sr2+
Experiment
Radical name: Barium
Chemical symbol of Radical: Ba2+
Observation
Result
-ve
The cation is not NH4+
Salt solution + dil. HCl
-ve
The cation is not from Group I
Salt solution + dil. HCl +
-ve
The cation is not from Group II
-ve
The cation is not from Group III
-ve
The cation is not from Group IV
Solid salt + Na2CO3 (solid)
+ drops of water
H2S
Salt solution + NH4Cl +
NH4OH
Salt solution + NH4Cl +
NH4OH + H2S
Salt solution + NH4Cl +
White ppt. is formed
NH4OH + (NH4)2CO3
The ppt. may be CaCo3, SrCo3
or BaCO3
the cation may be Ca2+, Sr2+ or
Ba2+
Salt solution + CaSO4
White ppt. is formed
The ppt. is BaSO4
the cation is Ba2+
Salt solution + K2CrO4
Yellow ppt. is formed, insoluble in
The ppt. is BaCrO4
acetic acid
Flame test
Pale apple green colour is appeared
the cation is Ba2+
Detection for Magnesium
Radical name: Magnesium
Chemical symbol of Radical: Mg2+
Experiment
Observation
Result
Solid salt + Na2CO3 (solid)
-ve
The cation is not NH4+
Salt solution + dil. HCl
-ve
The cation is not from Group I
Salt solution + dil. HCl +
-ve
The cation is not from Group II
-ve
The cation is not from Group III
-ve
The cation is not from Group IV
-ve
The cation is not from Group V
+ drops of water
H2S
Salt solution + NH4Cl +
NH4OH
Salt solution + NH4Cl +
NH4OH + H2S
Salt solution + NH4Cl +
NH4OH + (NH4)2CO3
Salt solution + NaOH
White ppt. is formed
The ppt. is Mg(OH)2
the cation is Mg2+
Salt solution + (NH4)2CO3
White ppt. is formed
The ppt. is MgCO3
Salt solution + Na3PO4 +
White ppt. is formed
The ppt. is Mg(NH4)PO4
NH4Cl + NH4OH
Detection for Potassium & Sodium
Radical name: Potassium
Chemical symbol of Radical: K+
Experiment
Observation
Result
Solid salt + Na2CO3 (solid)
-ve
The cation is not NH4+
Salt solution + dil. HCl
-ve
The cation is not from Group I
Salt solution + dil. HCl +
-ve
The cation is not from Group II
-ve
The cation is not from Group III
-ve
The cation is not from Group IV
-ve
The cation is not from Group V
-ve
The cation is not Mg2+
+ drops of water
H2S
Salt solution + NH4Cl +
NH4OH
Salt solution + NH4Cl +
NH4OH + H2S
Salt solution + NH4Cl +
NH4OH + (NH4)2CO3
Salt solution + NaOH
Salt solution +
Yellow ppt. is formed
The ppt. is K3[Co(NO2)6]
the cation is K+
Na3[Co(NO2)6]
Salt solution + Tartaric
White ppt. is formed from conc.
The ppt. is potassium hydrogen
acid solution
solution
tartarate
Flame test
Violet colour is appeared
the cation is K+
Radical name: Sodium
Chemical symbol of Radical: Na+
Experiment
Observation
Result
Solid salt + Na2CO3 (solid)
-ve
The cation is not NH4+
Salt solution + dil. HCl
-ve
The cation is not from Group I
Salt solution + dil. HCl +
-ve
The cation is not from Group II
-ve
The cation is not from Group III
-ve
The cation is not from Group IV
-ve
The cation is not from Group V
Salt solution + NaOH
-ve
The cation is not Mg2+
Salt solution +
-ve
The cation is Na+
+ drops of water
H2S
Salt solution + NH4Cl +
NH4OH
Salt solution + NH4Cl +
NH4OH + H2S
Salt solution + NH4Cl +
NH4OH + (NH4)2CO3
Na3[Co(NO2)6]
Flame test
Golden yellow colour is appeared
the cation is Na+
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