It is used to separate small solid particles from a liquid.
It is used either to remove impurities from an organic solution or to isolate an organic solid.
The two types of filtration commonly used in organic chemistry laboratories are gravity filtration and vacuum or suction filtration.
Procedure Step 1: Prepare the lead(II) sulphate. Pour 30 cm3 of sodium sulphate into a beaker containing 50 cm3 of lead(II) nitrate solution. Stir the reaction mixture with a glass rod. Aqueous sodium sulphate Aqueous lead(II) nitrate Glass rod
Procedure Step 2: Fold the filter paper. Fold a piece of filter paper as shown. Place it in a filter funnel. Moisten it with a little distilled water.
Procedure Step 3: Filter the mixture. Pour the reaction mixture into the filter funnel that is lined with filter paper. Collect the filtrate that passes through the filter paper in a conical flask. filtrate filter paper residue reaction mixture
Procedure Step 4: Collect the residue The residue is lead(II) sulphate. Wash the residue with distilled water. Then dry the residue on a piece of filter paper. Distilled water Dry the lead(II) sulphate
Lead(II) sulphate can be separated from sodium sulphate by filtration because the filter paper acts as a sieve.
A liquid can pass through the pores of the filter paper but a solid cannot do so.
Upon filtration, the solid (lead II sulphate) that remains on the filter paper is called the residue. The liquid (sodium sulphate) that passes through the filter paper is called the filtrate.
filtrate residue Filter paper Small particles of liquid pass through and become the filtrate Large insoluble particles are trapped by the filter paper and become the residue
Animation on filtration http://www.saskschools.ca/curr_content/science10/unita/redon17.html