identy of any one cation and anion from the following given salt
1.caco3
2.Bacl2
3.zns
4.pb(no3)2
1.physical characteristics of salt
2. dry and wet test for cation
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1. : we can identify the cation and anion in a given salt by using physical characteristics like color, taste, odor, melting point, solubility product etc..
from colors we observed : potassium dichromate, K2Cr2O7 ( orange) , potassium permanganate,KMnO4(violet), Ferric oxide, Fe3O4 (black), Ferrous sulphate , FeSO4.7H2O(green) etc.. here you can see same cation for different anions having different colours.
2. : borax bead test is mostly used in case of dry test for cations. This test is employed only for coloured salts because borax reacts with metal salts to form metal borates or metals, which have characteristic colours. see attachment to understand it.
see flow chart to understand wet test of cations.
3. : The identification of the radicals is first done on the basis of the preliminary tests. The Dry heating test is one of the preliminary tests performed earlier which may give some important information about the acid radical present. The other preliminary tests are based on the fact that:
CO3²-, S²-, NO2- and SO3²- react with dil. H2SO4 to give out CO2, H2S, NO2, and SO2 gases respectively. These gases on identification indicate the nature of the anion present in the salt.
Cl-,Br-, NO3- and C2O4²- and CH3COO- react with conc.H2SO4 but not with dil. H2SO4 to produce characteristic gases.
SO4²- and PO4³- neither react with dil H2SO4 nor conc. H2SO4.
so, we can identified the anions by using H2SO4.
4. :- as it is clear by name. Confirmatory tests are the tests required to confirm the analysis. you can confirm the cation and anions by using these test. there are many process which are helpful to confirm a cation or an anion in a given salt. like confirmatory test for NH4+ ion, Ammonia gas evolved by the action of sodium hydroxide on ammonium salts reacts with hydrochloric acid to give ammonium chloride, which is visible as dense white fume
from colors we observed : potassium dichromate, K2Cr2O7 ( orange) , potassium permanganate,KMnO4(violet), Ferric oxide, Fe3O4 (black), Ferrous sulphate , FeSO4.7H2O(green) etc.. here you can see same cation for different anions having different colours.
2. : borax bead test is mostly used in case of dry test for cations. This test is employed only for coloured salts because borax reacts with metal salts to form metal borates or metals, which have characteristic colours. see attachment to understand it.
see flow chart to understand wet test of cations.
3. : The identification of the radicals is first done on the basis of the preliminary tests. The Dry heating test is one of the preliminary tests performed earlier which may give some important information about the acid radical present. The other preliminary tests are based on the fact that:
CO3²-, S²-, NO2- and SO3²- react with dil. H2SO4 to give out CO2, H2S, NO2, and SO2 gases respectively. These gases on identification indicate the nature of the anion present in the salt.
Cl-,Br-, NO3- and C2O4²- and CH3COO- react with conc.H2SO4 but not with dil. H2SO4 to produce characteristic gases.
SO4²- and PO4³- neither react with dil H2SO4 nor conc. H2SO4.
so, we can identified the anions by using H2SO4.
4. :- as it is clear by name. Confirmatory tests are the tests required to confirm the analysis. you can confirm the cation and anions by using these test. there are many process which are helpful to confirm a cation or an anion in a given salt. like confirmatory test for NH4+ ion, Ammonia gas evolved by the action of sodium hydroxide on ammonium salts reacts with hydrochloric acid to give ammonium chloride, which is visible as dense white fume
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