[venous]

hi 
now if in this question " write short notes on fractional precipitation "  was in my exam I'd answer :
fractional precipitation means the removal of some ions from solution with precipitation while leaving other ions that have the same proparties in the solution by adding a precipitating agent . the precipitation will be according to solubility product of ions and the smaller solubility product will be precipitated first >

that would be my answer ,,,,, now i need some one to tell me if it is right and complete or do i need to write and know more about fractional precipitation  ?

thanx 

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[AWK]

the smaller solubility product

This is only true for the same type of Ksp eq AgCl, AgBr
but not should be true for eg:
Ca3(PO4)2 and AlPO4