Question

can anyone tell me about the test for confirming the presence of STRONTIUM and OXALATE. plzzzzzz

Answer 1

1. For Strontium, Sr 2+
To 10 drops of the solution , add 5 drops of ethanol (C 2 H 5OH). Then add 3 M (6 N) H 2 SO4 dropwise until precipitation is complete. Heat the sample in a water bath for a few minutes. Test again for complete precipitation by adding 1 more drop of sulfuric acid. Centrifuge and decant the supernatant. If any further tests will be carried out on the supernatant liquid, heat it in a boiling water bath to expel the C 2 H 5OH, which could interfere with further tests. The white precipitate of SrSO 4 confirms the presence of strontium.

2. The reactions for oxalate ions- 2MnO4- + 16H+ + 5C2O4-2 ---------> 2Mn+2 +8H2O + 10 CO2 Oxalate ions are C2O4

Lets take eg of conc. H2S04 and then,
Concentrated sulphuric acid decomposes oxalate ions into Carbon monoxide and carbondioxide. Readers shouldn't take long to realize that the oxalate ions have decomposed through a disproportionation reaction. If the evolution of the two gases is confirmed, we can say that sulphuric acid reacted with oxalate ions.
If the evolved gaseous mixture is passed through limewater, it will turn milky and finally colourless. Carbon Monoxide in the mixture will burn with a blue flame to produce carbon dioxide. The two gases are confirmed in this way, confirming the presence of the oxalate ion.