Question

What kind of filtration should be performed when one wants to further work with the solution, while getting rid of soluble impurities? Why?

Answer 1

the basic recrystallization plan is to dissolve an impue solid in a hot solvent, then cool the solution to that the desired molecules recrystallize while the impurties remain in solution.Subsequent filtration separates the solid crystal from the liquid solvent.

But sometime impurities not dissolve completely in solvent even after temperature increasing, hence they are necessary to remove from the solvent for further work, they are removed by gravity filteration.