Separating Ions by Selective Precipitation
Problem: A solution consists of 0.10 M AgNO3 and 0.15 M Cu(NO3)2.Calculate the [I -] that can be used to separate the metals as their iodides.
Kspof AgI = 8.3 x 10-17; Kspof CuI = 1.0 x 10-12.
Plan: Since the two iodides have the same formula type (1:1), directly compare their Ksp values. NOTE: CuI is about 100,000 times more soluble than AgI. Therefore, AgI precipitates first. Solve for [I -], which is the concentration for a saturated solution of AgI.
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