First of all, we made the known matrix.
We added five drops of each 0.2 M anion solution i.e NO3, SO4, C2O4 etc.? Initial reaction of flow chart.
We added 15-20 drops of saturated Ba (OH)2 (eq) solution in our known mixture to separate insoluble Barium salts (Baso4 , Ba C2 O4) form soluble nitrate solution. We separated the solid ppts formed (Baso4 (s) , BaC2O4(s) from supernatant (that contain No3 (aq) using plastic pipette. Before decanting the supernatant , we added additional 2-3 drops of reagent (i.e. Ba(OH)2 (eq)) ,if more ppts are formed means reaction was not completed , so we added additional reagent until ppts stop appearing further , Now all the Barium salt (Baso4 , BaC2 O4) were separated successfully and we decanted the supernatant in empty test tube .
? Testing of supernatant.Supernatant when separated from ppts , it contained only No3(aq) ion because other two ions were completely precipitated out already so we confirmed the presence of No3 in supernatant by producing gas. ? We added 3-5 granules of Aluminium (s) and enough 6M NaOH to make supernatant solution Present in test tube basic . Ammonia gas was evolved from test tube. We plugged the test tube with some support and suspended the wet red litmus paper above test tube without allowing it to touch the liquid. Red litmus turned blue when it came into contact with ammonia gas evolved. Thus we confirmed the presence of No3 ion in supernatant.
? Testing of the precipitates.Next , we tested our precipitates. Ppts contain BaSo4 and BaC2O4. we added enough of 6M HNO3 (aq) acid so that some portion of ppts which was containing C2O4 anion was dissolved in acid. When all the ppts containing C2O4 were dissolved in acid and there was no more dissolution by further addition of acid.
When we stopped addition of acid further light white smoke was observed which was actually due to formation of solid BaSO4. we separated this ppts from supernatant by using plastic micropipette. We successfully ? Final step.
While performing the final step , PH must be neutral (7). Solution was acidic ,so we added 6M NaOH enough to make it neutral. Then we added 1M solution of Pb(NO3)2 (aq) and completely precipitated the final product i.e. PbC2O4.
Final ppts were again separated from solution again by using plastic pipette. Reaction was complete when no more precipitation could be observed by further addition of reagent i.e. Pb(NO3)2.