Determination
Of SO4 in Na2SO4.10H2O
THEORY
Sulfuric
can be precipitated out of salt solution as Barium Sulfate (BaSO4)
in acid condition to avoid precipitation of another Ba, such as BaCO3
and Ba3(PO4)2. To avoid coprecipitation of
BaCl2 should dilute little by little. Aging conducted in hot
conditions to enlarge the crystal and to reduce coprecipitation. The sediment
of BaSO4 was so subtle so make it’s easy to creep upward. In ignition sediment of BaSO4 can
be reduced by carbon from filter paper to be BaS.
BaSO4
+ 4C ㅡ> BaS
+ 4CO
BaSO4
+ 4 H2O ㅡ> BaS
+ 4 H2O
Therefore,
after the carbon is lost, the rest of incandescent added 1 drop of concentrated H2SO4 and burning it again to
change BaS become BaSO4.
BaS + H2SO4 ㅡ> BaSO4 +
H2S
Basic
In condition acid and heat sulfuric can be
precipitated with BaCl2 become BaSO4 the colour is white
,and after burned remains as BaSO4.
Reaction
Na2SO4 +BaCl2 ㅡ> BaSO4 + 2NaCl
BaSO4 + 4C ㅡ> BaS
+ 4CO
Bas + H2SO4 ㅡ>
BaSO4 + H2S
Procedur
- Prepare two 400ml beaker glass
- Measured carefully ±0,5 gram sample ,disslved with ± 50ml of distilled water in a 400ml beaker glass .After that gived HCl 4N drop by drop ,and then boiled it
- Gived ± 10ml BaCl2 0,5N to the second beaker glass ,and rinsed with ± 50ml of distilled water ,and boiled it
- Dissolved BaCl2 is poured slowly into a solution of the sample in the first beaker glass
- Stired the sediment in beaker glass ,and put it in water boiler about ± 1 hour .
- A perfect test of precipitation (the pellucid fluid dropped by BaCl2 0,5N)
- Filltered the precipitate of BaSO4 with the barite fillter paper (whatman No.42) washed the precipitate with hot water until it free from chloride and sour
- Dried in oven ,charred ashify until the carbon is vanish .Cooled it down (in opened air)
- Put the porcelain cruicible with ash ,into the fume hoods and add one drop of H2SO4-p
- Heat up with little tecklu fire ,until the white smooke vanish
- Put out from the fume hoods ,candescane it,cooled down in desicator weight it
- Do it frequently until you get the absolute weight
Calculation
- Practical levels
[
( SO4 / BaSO4 )x ash weight] / sample weight x
100%
- Theoritical levels
[ ( SO4 / Na2SO4 . 10 H2O
) x
100% ]
- Purity
(
Practical levels / Theoritical levels ) x
100%
- Faultness
100
% -
Purity
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