Be sure that the hot solution is added in small quantities to thefluted filter paper, because cooling at this stage may cause prematurecrystallization. Keep the unfiltered solution hot at all times. Ifyou have difficulty keeping the solution from crystallizing on thefilter paper, add additional hot solvent to the flask containing theunfiltered solution and reheat it to the boiling point before continuingthe filtration. When the filtration is complete, add a boilingstone or stick and boil away the extra solvent you added.When all the hot solution has drained through the filter paper,check to see whether any crystallization occurred in the Erlenmeyerreceiving flask due to rapid cooling during the filtration step. If ithas, reheat the mixture to dissolve the solid completely before allowingthe solute to crystallize slowly.
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