If a wash was used to neutralize an organic layer, test the aqueous layer it is in contact with. Most often a wash is used to neutralize trace amounts of acid.
If the aqueous layer is the top layer, insert a glass stirring rod, and touch the rod to blue litmus paper.
An acidic solution turns the blue paper pink (or red), while a neutral solution makes the paper look wet.
If the aqueous layer is the bottom layer,remove and test the pH of an aliquot:
Place your finger atop a pipette and insert it so the tip is in the bottom layer.
|Let go of your finger and allow a small amount of the bottom layer to withdraw into the pipette.
Place your finger atop the pipette again, then remove the aliquot from the funnel.
Test the pH of the aliquot on blue litmus paper.
If still acidic, repeat the neutralization washes on the organic layer.