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SEMI – MICRO QUALITATIVE ANALYSIS OF SIMPLE INORGANIC SALT _______________________________________________________________
CATIONS: Pb2+ ,Hg2+ ,Cu2+ ,Cd2+ , Ag+ , Fe2+ , Fe3+ , Al3+ , Zn2+ , Mn2+ , Co2+ , Sr2+ , Ba2+ , Mg2+ , NH4+ ANIONS: CO32- , S2- , SO32- , SO42- , NO2- , NO3- , Cl- , Br2- , PO43- , CH3COO-

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PRELIMINARY TESTS
1. Note the state (amorphous or crystalline) and colour of salt. 2. Test the solubility of the salt in the following solutions: i. Water (cold and hot) ii. Dilute HCl (cold and hot) iii. Dilute HNO3 (cold and hot)

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IDENTIFICATION OF ACID RADICALS (ANIONS)
This part is the classified into three groups:

FIRST GROUP OF ACID RADICALS
The acid radicals involved in this group are carbonate(CO32-), Sulphide(S2-), Sulphite(SO32-), Thiosulphate(S2O32-) and nitrate(NO2-). The group reagent is dilute hydrochloric acid. EXPERIMENT Salt + dil. HCl OBSERVATION Effervescence or evolution of gases (a) Colourless, odourless gas turns lime water milky (b) Colourless with rotten eggs smell and turns lead acetate paper black. (c) Colourless gas with suffocating smell. Heat and pass the gas through acidified K2Cr2O7 solution. The solution turns green (d) Colourless gas with suffocating smell with a yellow ppt. of sulphur in the test tube. Heat and pass the gas through acidified K2Cr2O7 solution. The solution turns dark blackish green. (e) Colourless gas followed by brown gas and it turns starch iodide paper blue. (f) Colourless gas with the smell of vinegar. INFERENCE 1st group of acid radicals is present. The acid radical may be CO32- or HCO3Sulphide(S2-) is confirmed.

SO32- is confirmed.

S2O32- is confirmed.

NO2- is confirmed. The acid radical may be CH3COO-

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Tests to distinguish between CO32- and HCO3EXPERIMENT Salt + water, boil and pass the gas through lime water OBSERVATION (a) Lime water does not