Cations
Test Observation InferencePhysical Appearance Colour White NH4+, Pb2+, Al3+ , Zn2+, Ba2+,
Ca2+ , Sr2+ and Mg2+ Blue Cu2+ Green Ni2+ Brown Fe3+ Red Co2+ Light pink Mn2+Odour Smell of NH3 NH4+ Smell of vinegar CH3COO- Smell of rotten eggs H2-Dry Heating Colourless gas evolved CO32- , SO32-, S2- and Cl- Blown gas evolved Br-, NO3- Violet gas evolved I- Crackling sound Pb(NO3)2 and Ba(NO3)2 Brown residue Cu2+Flame Test Greenish blue Cu2+ Light green Ba2+ Brick red Ca2+ Crimson red Sr2+
Aim: - To identify the given inorganic compound for its acidic and basic radical.
Group Group Reagent RadicalsZero Group O.S. + NaOH + Heat NH4
+
I Group O.S. + HCl Pb2+
II Group O.S. + HCI + H2S Cu2+
III Group O.S. +NH4Cl + NH4OH AI3+ ,Fe3+
IV Group O.S. + NH4CI + NH4OH +H2S
Ni2+ ,Mn2+ , Zn2+ ,Co2+
V Group O.S. + NH4CI + NH4OH +(NH4)2CO3 Ba2+, Ca2+, Sr2+
VI Group O.S + NH4CI + NH4OH + NaH2PO4 Mg2+
Apparatus: - Chemical Reagent, Test Tube, Test Tube holder, Spatula, Burner
Physical Observation
1. Smell or odour 2. State 3. Colour 4. Solubility in H 2O
Basic Radical
Preliminary Test:-
Confirmatory Test:-
Acidic Radical
Preliminary Test:-
Confirmatory Test:-
Result:- The given salt contains ____as acidic radical and ____as basic radical.Group 0:- NH4
+
Preliminary Test:-
S.N.Experiment Observation Inference
1. Smelled the salt. Ammonical smell. NH4+ may be present.
Confirmatory Test:-
S.N.Experiment Observation Inference
1. Added sodium hydroxide solution to the salt.
Ammonical smelling gas evolved.
NH4+ confirmed.
Chemical Equations:- Ionic equation:- NH4++OH- --- NH3+H2O
Group 1:- Pb 2+ , Ag +
Preliminary Test:-
ExperimentObservation Inference
Smelled the salt. No Ammonical smell. NH4+ absent.
Added dilute hydrochloric acid to original solution.
White coloured precipitate is formed.
Pb2+ may be present.
Confirmatory Test:-
ExperimentObservation Inference
Added potassium iodide. Yellow coloured precipitate formed.
Pb2+ confirmed.
Chemical Equations:-
Ionic equation:-Pb2+(aq)+ HCl (aq) -- PbCl2 (white)
Pb2+(aq) +2I- --(aq) PbI2(s) (Yellow)
Ag1+
Preliminary Test:-
ExperimentObservation Inference
Smelled the salt. No Ammonical smell. NH4+ absent.
Added dilute hydrochloric acid to original solution.
White coloured precipitate is formed.
Pb2+, Ag1+ may be present.
Added precipitate in hot water.
No effect. Ag1+ may be present.
Confirmatory Test:-
ExperimentObservation Inference
Added potassium chromate to original solution.
Brick red coloured precipitate formed.
Ag1+ confirmed.
Chemical Equations:-
Ionic equation:- Ag++HCl(aq) -AgCl (s) white +H+
2AgCl(s)+K2Cr2O7 -- Ag2CrO4 Yellow +2KCl
Group 2:- Pb2+, Cu2+, As3+
Preliminary Test:- Pb2+
ExperimentObservation Inference
Smelled the salt. No Ammonical smell. NH4+ absent.
Added dilute hydrochloric acid to original solution.
No Effect. Pb2+ may be present.
Added H2S, hydrochloric acid to original solution.
Black coloured precipitate formed.
Pb2+ may be present.
Confirmatory Test:-
ExperimentObservation Inference
Added potassium iodide to original solution. Yellow coloured precipitate formed.
Pb2+ confirmed.
Chemical Equations:- Ionic equation:- Pb2++HCl -- PbCl2(l) + 2H+
Pb2++ KI (aq) ----- PbI2(s) Yellow +2K+
Cu2+
Group 3:- Fe3+, Al3+, As3+
IRON
Preliminary Test:-
ExperimentObservation Inference
Smelled the salt. No Ammonical smell. NH4+absent.
Added dilute hydrochloric acid to original solution.
No Effect. Pb2+ may be present.
Added H2S, hydrochloric acid to original solution.
No Effect. Pb2+, Cu2+, As3+ absent.
Added dilute hydrochloric acid, concentrated nitric acid and boiled solution. Then cooled it and added solid ammonium hydroxide.
Reddish Brown precipitate formed.
Fe3+may be present.
Confirmatory Test:-
ExperimentObservation Inference
Dissolved the precipitate formed with hydrochloric . Added potassium sulphocyanide.
Blood red colouration. Fe3+ confirmed.
Chemical Equations:-
Ionic equation:-
Al3+
Preliminary Test:-
ExperimentObservation Inference
Smelled the salt. No Ammonical smell. NH4+ absent.
Added dilute hydrochloric acid to original solution.
No Effect. Pb2+ may be present.
Added H2S, hydrochloric acid to original solution.
No Effect. Pb2+ , Cu2+, As3+ absent.
Added dilute hydrochloric acid, concentrated nitric acid and boiled solution. Then cooled it and added solid ammonium hydroxide.
Gelatinous white precipitate formed.
AI3+ may be present.
Confirmatory Test:-
ExperimentObservation Inference
Dissolved the precipitate formed with hydrochloric acid and added drops of blue litmus. Then added ammonium hydroxide till alkaline.
Blue coloured precipitate floated on surface .
AI3+ confirmed.
Chemical Equations:-Ionic equation:-
Group 4:- Mn 2+ , Zn 2+ , Ni 2+ , Co 2+
MANGANESE
Preliminary Test:-
ExperimentObservation Inference
Smelled the salt. No Ammonical smell. NH4+ absent.
Added dilute hydrochloric acid to original solution.
No Effect. Pb2+may be present.
Added H2S, hydrochloric acid to original solution.
No Effect. Pb2+, Cu2+, As3+ absent.
Added dilute hydrochloric acid, concentrated nitric acid and boiled solution. Then cooled it and added solid ammonium hydroxide.
No Effect. AI3+ ,Fe3+ absent.
Passed H2S gas through above formed solution.
Flesh(buff) coloured precipitate formed.
Mn2+ may be present.
Confirmatory Test:-
ExperimentObservation Inference
Added lead dioxide to above solution, then added concentrated nitric acid. Boiled it.
Pink Colouration formed. Mn2+ Confirmed.
Chemical Equations:-Ionic equation:-
ZINC
Preliminary Test:-
ExperimentObservation Inference
Smelled the salt. No Ammonical smell. NH4+ absent.
Added dilute hydrochloric acid to original solution.
No Effect. Pb2+may be present.
Added H2S, hydrochloric acid to original solution.
No Effect. Pb2+, Cu2+, As3+ absent.
Added dilute hydrochloric acid, concentrated nitric acid and boiled solution. Then cooled it and added solid ammonium hydroxide.
No Effect. AI3+ ,Fe3+ absent.
Passed H2S gas through above formed solution.
White coloured precipitate formed.
Zn2+ may be present.
Confirmatory Test:-
ExperimentObservation Inference
Dissolved the precipitate in concentrated hydrochloric acid and boiled it.Added potassium ferrocyanide to it
Bluish white coloured precipitate formed.
Zn2+ Confirmed.
Chemical Equations:-Ionic equation:-
NICKEL
Preliminary Test:-
ExperimentObservation Inference
Smelled the salt. No Ammonical smell. NH4+ absent.
Added dilute hydrochloric acid to original solution.
No Effect. Pb2+ may be present.
Added H2S, hydrochloric acid to original solution.
No Effect. Pb2+, Cu2+, As3+ absent.
Added dilute hydrochloric acid, concentrated nitric acid and boiled solution. Then cooled it and added solid ammonium hydroxide.
No Effect. AI3+ ,Fe3+ absent.
Passed H2S gas through above formed solution.
Black coloured precipitate formed.
Co2+ or Ni2+ may be present.
Dissolved the precipitate in aqua regia.Evaporated residue.
Yellow coloured residue remained.
Ni2+ may be present.
Confirmatory Test:-
ExperimentObservation Inference
Dissolved the yellow residue in water. Added ammonium hydroxide till alkaline then added dimethylglyxoglime solution.
Bright red precipitate formed.
Ni2+ confirmed.
Chemical Equations:-Ionic equation:-
COBALT
Preliminary Test:-
ExperimentObservation Inference
Smelled the salt. No Ammonical smell.
NH4+ absent.
Added dilute hydrochloric acid to original solution.
No Effect. Pb2+ may be present.
Added H2S, hydrochloric acid to original solution.
No Effect. Pb2+, Cu2+, As3+ absent.
Added dilute hydrochloric acid, concentrated nitric acid and boiled solution. Then cooled it and added solid ammonium hydroxide.
No Effect. AI3+ ,Fe3+ absent.
Passed H2S gas through above formed solution.
Black coloured precipitate formed.
Co2+ or Ni2+ may be present.
Dissolved the precipitate in aqua regia.Evaporated residue.
Blue coloured residue remained.
Co2+ may be present.
Confirmatory Test:-
ExperimentObservation Inference
Dissolved the blue residue in water.Added ammonium sulphocyanide to it.
Blue coloured layer floated on surface .
Co2+confirmed.
Chemical Equations:-Ionic equation:-
Group 5:- Ca 2+ , Ba 2 + , Sr 2+
CALCIUM
Preliminary Test:-
ExperimentObservation Inference
Smelled the salt. No Ammonical smell. NH4+ absent.
Added dilute hydrochloric acid to No Effect. Pb2+may be present.
original solution.Added H2S, hydrochloric acid to original solution.
No Effect. Pb2+, Cu2+, As3+ absent.
Added dilute hydrochloric acid, concentrated nitric acid and boiled solution. Then cooled it and added solid ammonium hydroxide.
No Effect. AI3+ ,Fe3+ absent.
Passed H2S gas through above formed solution.
No Effect. Ni2+ ,Mn2+ , Zn2+ ,Co2+ absent.
Added ammonium carbonate to above solution.
White precipitate is formed.
Ba(II), Sr(II), Ca(II) may be present.
Confirmatory Test:-
ExperimentObservation Inference
Dissolved precipitate in acetic acid and boiled it. Added few drops of ammonium oxalate to above solution and then added ammonium hydroxide.
White precipitate is formed.
Ca2+ Confirmed.
Chemical Equations:-Ionic equation:-
BARIUM
Preliminary Test:-
ExperimentObservation Inference
Smelled the salt. No Ammonical smell. NH4+ absent.
Added dilute hydrochloric acid to original solution.
No Effect. Pb2+may be present.
Added H2S, hydrochloric acid to original solution.
No Effect. Pb2+, Cu2+, As3+ absent.
Added dilute hydrochloric acid, concentrated nitric acid and boiled solution. Then cooled it and added solid ammonium hydroxide.
No Effect. AI3+ ,Fe3+ absent.
Passed H2S gas through above formed solution.
No Effect. Ni2+ ,Mn2+ , Zn2+ ,Co2+ absent.
Added ammonium carbonate to above solution.
White precipitate is formed.
Ba2+, Ca2+, Sr2+ may be present.
Confirmatory Test:-
ExperimentObservation Inference
Dissolved precipitate in acetic acid and boiled it.Added few drops of potassium chromate to above solution.
Yellow precipitate is formed. Ba2+ Confirmed.
Chemical Equations:- Ionic equation:-
STRONTIUM
Preliminary Test:-
ExperimentObservation Inference
Smelled the salt. No Ammonical smell. NH4+ absent.
Added dilute hydrochloric acid to original solution.
No Effect. Pb2+may be present.
Added H2S, hydrochloric acid to original solution.
No Effect. Pb2+, Cu2+, As3+absent.
Added dilute hydrochloric acid, concentrated nitric acid and boiled solution. Then cooled it and added solid ammonium hydroxide.
No Effect. AI3+ ,Fe3+ absent.
Passed H2S gas through above formed solution.
No Effect. Ni2+ ,Mn2+ , Zn2+ ,Co2+ absent.
Added ammonium carbonate to above solution.
White precipitate is formed.
Ba2+, Ca2+, Sr2+ may be present.
Confirmatory Test:-
ExperimentObservation Inference
Dissolved precipitate in acetic acid and boiled it. Added few drops of ammonium sulphate to above solution and then added ammonium hydroxide.
White precipitate is formed.
Sr2+ Confirmed.
Chemical Equations:-Ionic equation:- Sr2++(NH4)2CO3(aq) --SrCO3(s)white +2NH4+(aq)
SrCO3(s) 2CH3COOH(aq) -- (CH3COO)2Sr +CO2(g) +H2O(l)
Sr2+(aq)+(NH4)2SO4(aq) --Sr SO4(s)white +2NH4+(aq)
Group 6:- Mg 2+
Preliminary Test:-
ExperimentObservation Inference
Smelled the salt. No Ammonical smell. NH4+ absent.
Added dilute hydrochloric acid to original solution.
No Effect. Pb2+may be present.
Added H2S, hydrochloric acid to original solution.
No Effect. Pb2+, Cu2+, As(III) absent.
Added dilute hydrochloric acid, concentrated nitric acid and boiled solution. Then cooled it and added solid ammonium hydroxide.
No Effect. AI3+ ,Fe3+ absent.
Passed H2S gas through above formed solution.
No Effect. Ni2+ ,Mn2+ , Zn2+ ,Co2+ absent.
Added ammonium carbonate to above solution.
No Effect. Mg 2+ may be present.
Confirmatory Test:-
ExperimentObservation Inference
Added ammonium chloride, ammonium hydroxide and disodium hydrogen phosphate to original solution.
White precipitate is formed. Mg2+ Confirmed.
Chemical Equations:-
Ionic equation:-Mg2++HPO42-(aq) +NH4
+(aq) --- Mg(NH4)PO4 white +H+