IMAGE. A dirty volumetric flask. Note that beads of water have formed on the flask walls indicating that the flask is still dirty.
Clean a volumetric flask before use. Rinse the flask several times with the solvent that will be used to prepare the solution. Inspect the flask to ensure that it is clean. Grease or other contaminants may cause the water to bead on the inside surface of the flask. The region between the volumetric mark and the mouth of the flask is a good place to look for beading. If the flask appears to be dirty, make another attempt to clean the flask.
What is the best way to eliminate water clinging to the walls of the flask?
Answer: C. Wash the flask with laboratory soap and rinse it thoroughly.
Do not attempt to dry the flask with a paper towel or cheesecloth. The neck is relatively narrow, and putting a paper towel or cheesecloth into it is difficult. Also, you should not add distilled water to the flask to wash the beads of water down the sides, since the solution to be diluted should be added to the flask before any water is added.
What is the best way to eliminate water clinging to the walls of the flask?