AP Chemistry Lab Manual - PC\|MAC

The iron and manganese hydroxides will spin down first because of the greater densities and the aluminum hydroxide will be on top. Add 6M HC2H3O2 to second half of decantate from step 9 until acidic to litmus paper. Add 1-2 drops 0.1 M Pb(C2H3O2)2. Let stand for 3 minutes. A white or yellow precipitate is a positive test for CrO42- ions. ................
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