Division 6.5.11 Carry out a third extraction by further repeating the operations described in 6.5.3. to 6.5.8. inclusive, but using only 15 ml of diethyl ether (4.4.) and 15 ml of light petroleum (4.5.); use the ether to rinse the inside of the neck of the extraction flask. If necessary, raise the interface to the middle of the neck of the flask to enable the final decantation of solvent to be as complete as possible.

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