Page 66 - Statistics presented by Dr. Sara Ismail Aborass

9/8/2023

• Reprecipitation
An analyte ppt is washed, dissolved in
a pure solution and reprecipitated.
It is applicable when the ppt is easy
to be redissolved.
During the second pption, the amount
of contaminant absorbed will be
lower since its concentration in the
solution is less

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c)Coprecipitation by occlusion
• i) Internal occlusion (occlusion within

crystals)
• If the crystal grows rapidly, no time for

the surfacely adsorbed impurity to be
desorbed. So it may be entrapped
within the crystal (enclosed impurity)
(occluded) (internally adsorbed)

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