Experiment 1

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Experiment 1
Refining Sodium Chloride
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Purposes
1. To master the usage of glassware washing,
alcohol burner and platform balance. 2. Practice
the basic operation of dissolving,
filtrating, evaporating, concentrating and
drying. 3. To learn the general theories and
methods of refining sodium chloride.
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Principles

• Crude salt usually contains soluble ions, such as
  Ca2? Mg2?SO42- ?K and other insoluble
  impurities. The insoluble material can be removed
  by filtrating the solution of crude salt and the
  soluble ones can be eliminated by adding the
  proper reagents (for example, BaCl2, Na2CO3, HCl,
  etc.) to the solution of crude in which the
  precipitate can form.

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Reactions
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Procedure
1.Refining sodium chloride
15ml H2O
BaCl 2
Weigh out 4g crude salt
dissolving
?
?
Adding NaOH,Na2CO3
solution (evaporating dish) K?OH- ?CO32-
filtrating
pH4-6
concentrating
NaCl crystal
HCl
drying
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2.Test the purity of the purified salt
test the SO42-
BaCl 2 solution
test the Ca2 ion
(NH4)2C2O4 solution
test the Mg2 ion
magnesium agent
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Recording and handling data 1. Refining
the sodium chloride weight of crude salt
m1 g, weight of purified
salt m2 g
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• 2. Test the purity of the purified salt

Item crude salt Solution purified salt solution
Test the SO42- ion Phenomenon Conclusion Phenomenon Conclusion
Test the Ca2 ion Phenomenon Conclusion Phenomenon Conclusion
Test the Mg2 ion Phenomenon Conclusion Phenomenon Conclusion