IDENTIFY THE CATIONIC AND ANIONIC RADICAL IN GIVEN UNKNOWN SALT A BY PERFORMING DRY AND WET TEST FOR CATIONIC RADICAL AND ANIONIC RADICAL IN HINDI PRATICA
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Hey!!
Dry test means testing a substance by its physical properties like colour, density, etc.
Wet test means testing a substance by adding suitable reagents.
Add little Sodium hydroxide(NaOH) solution into the given salt.
If the salt contains the following cations, the following coloured precipitates are obtained:
Copper: Pale blue
Ferrous: Dirty green
Ferric: Yellowish brown
Zinc: Gelatinous white
Lead: Chalky white
Calcium: Curdy white
Magnesium: Milky white
Aluminium: Shiny white
On adding excess sodium hydroxide solution, the white precipitates of zinc, lead and aluminium dissolves; others do not.
Now to test for anions, add silver nitrate solution on the given salt.
If a white precipitate (of AgCl) is obtained which dissolves in excess ammonia solution, then Chloride ion is present.
Add Barium Chloride solution. If a white precipitate (of BaSO4) is obtained, which is insoluble in mineral acids, then the salt contains Sulphate radical.
Add freshly prepared ferrous sulphate solution with conc. H2SO4 into the given salt solution. If a brown ring (of Nitroso Ferrous Sulphate) appears, the salt contains Nitrate ions. Thanks....
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Sorry I have posted it in English!
Dry test means testing a substance by its physical properties like colour, density, etc.
Wet test means testing a substance by adding suitable reagents.
Add little Sodium hydroxide(NaOH) solution into the given salt.
If the salt contains the following cations, the following coloured precipitates are obtained:
Copper: Pale blue
Ferrous: Dirty green
Ferric: Yellowish brown
Zinc: Gelatinous white
Lead: Chalky white
Calcium: Curdy white
Magnesium: Milky white
Aluminium: Shiny white
On adding excess sodium hydroxide solution, the white precipitates of zinc, lead and aluminium dissolves; others do not.
Now to test for anions, add silver nitrate solution on the given salt.
If a white precipitate (of AgCl) is obtained which dissolves in excess ammonia solution, then Chloride ion is present.
Add Barium Chloride solution. If a white precipitate (of BaSO4) is obtained, which is insoluble in mineral acids, then the salt contains Sulphate radical.
Add freshly prepared ferrous sulphate solution with conc. H2SO4 into the given salt solution. If a brown ring (of Nitroso Ferrous Sulphate) appears, the salt contains Nitrate ions. Thanks....
Follow to get more answers!
Sorry I have posted it in English!
Answered by
2
Sorry I could Answer in English . please translate it in Hindi while you note down these in your practicals note book.
Dry Test :
Borax Bead Test:
This test is to be performed only for coloured salts.
Borax [Na2B407.10H20] on heating gets fused and loses water of crytsllisation.
After melting it forms colouless liquid which later forms a clear transparent bead consisting of boric anhydride and sodium metaborate.
Na2B407.10H2O -------> Na2B4O7 +10H2O
Na2B4O7----> B2O3 +2 Na BO2
Boric anhydride is non volatile.
When treated with coloured salt , a colour bead of metal carbonate is formed.
*************************************************************
*Metal Hot Cold
***************************************************************
copper Green Blue
Iron yellowish brown yellow
Chromium yellow green
Manganese Violet amethyst
Cobalt blue blue
Nickel Violet reddish brown
**********************************************************************
Wet Test for Acid radicals :
salt is mixed with dil.H2SO4 and also with Conc.H2SO4
Based on the type of gas evolved . Inference is done .
****************************************************************************************
Observation Acid radical Confirmation Test
****************************************************************************************
1. evolution of CO₃²⁻ Gas turns lime water milky.colourless gas
2. Brown gas NO₂⁻ Add KI and starch solution. It turns blue colour
3. Smell of S₂⁻ Gas turns lead acetate paper blackrotten eggs
4.Pungent SO₃⁻ Turns acidiefed K2cR2O7 Sol green colourlessgas
5. Gives smell of CH3COO⁻ aq. +neutral FeCl2
vinegar gives blood red colour.
6.white/Yellow S₂O₃²⁻ aq.+AgNo3 white prpt ---> black.turbidity on warming
7. colourless Cl- add. MnO2 and heatpungent gas with white fumes pale green colour gas will be evolved
8. Reddish brown Br- add MnO2 and heatfumes brown gas is produed
9. Violet Pungentgas I- converts starch paper blue Layer test can be done
****************************************************************************************
Wet Test for Basic Radical :***************************************************************************************
Group Basic radicals Group Reagent Ppt as
*************************************************************************************
I Ag+, Hg2+, Pb2+ dil.HCl Chloride
II Cu2+,Cd2+,Pb2+,Hg2+ H2S gas +HCl Sulphides Bi3+,As3+, Sb3+ Sn2+
III Al3+,Cr3+Fe3+ NH4OH+NH4Cl Hydroxide
Iv Zn2+, Ni2+,Mn2+Co3+ H2S in Sulphides ammonical medium
V Ca2+,Ba2+ Sr2+ (NH4)2CO3 +NH4Cl Carbonates
VI Mg2+ ,Na+,K+ NH4OH , Na2HPO4 [for only Mg2+] white ppt
zero NH4+ ============ ***************************************************************************************
Dry Test :
Borax Bead Test:
This test is to be performed only for coloured salts.
Borax [Na2B407.10H20] on heating gets fused and loses water of crytsllisation.
After melting it forms colouless liquid which later forms a clear transparent bead consisting of boric anhydride and sodium metaborate.
Na2B407.10H2O -------> Na2B4O7 +10H2O
Na2B4O7----> B2O3 +2 Na BO2
Boric anhydride is non volatile.
When treated with coloured salt , a colour bead of metal carbonate is formed.
*************************************************************
*Metal Hot Cold
***************************************************************
copper Green Blue
Iron yellowish brown yellow
Chromium yellow green
Manganese Violet amethyst
Cobalt blue blue
Nickel Violet reddish brown
**********************************************************************
Wet Test for Acid radicals :
salt is mixed with dil.H2SO4 and also with Conc.H2SO4
Based on the type of gas evolved . Inference is done .
****************************************************************************************
Observation Acid radical Confirmation Test
****************************************************************************************
1. evolution of CO₃²⁻ Gas turns lime water milky.colourless gas
2. Brown gas NO₂⁻ Add KI and starch solution. It turns blue colour
3. Smell of S₂⁻ Gas turns lead acetate paper blackrotten eggs
4.Pungent SO₃⁻ Turns acidiefed K2cR2O7 Sol green colourlessgas
5. Gives smell of CH3COO⁻ aq. +neutral FeCl2
vinegar gives blood red colour.
6.white/Yellow S₂O₃²⁻ aq.+AgNo3 white prpt ---> black.turbidity on warming
7. colourless Cl- add. MnO2 and heatpungent gas with white fumes pale green colour gas will be evolved
8. Reddish brown Br- add MnO2 and heatfumes brown gas is produed
9. Violet Pungentgas I- converts starch paper blue Layer test can be done
****************************************************************************************
Wet Test for Basic Radical :***************************************************************************************
Group Basic radicals Group Reagent Ppt as
*************************************************************************************
I Ag+, Hg2+, Pb2+ dil.HCl Chloride
II Cu2+,Cd2+,Pb2+,Hg2+ H2S gas +HCl Sulphides Bi3+,As3+, Sb3+ Sn2+
III Al3+,Cr3+Fe3+ NH4OH+NH4Cl Hydroxide
Iv Zn2+, Ni2+,Mn2+Co3+ H2S in Sulphides ammonical medium
V Ca2+,Ba2+ Sr2+ (NH4)2CO3 +NH4Cl Carbonates
VI Mg2+ ,Na+,K+ NH4OH , Na2HPO4 [for only Mg2+] white ppt
zero NH4+ ============ ***************************************************************************************
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