Which of the following procedures, if either, is more accurate when making a 1/5
ID: 479038 • Letter: W
Question
Which of the following procedures, if either, is more accurate when making a 1/50 dilution of a solution? Transfer 1 mL with a pipet into a 50-mL volumetric flask. Both procedures have the same accuracy. Transfer 20 mL with a pipet into a 1-L volumetric flask. How can the accuracy of either procedure be improved? Use an Erlenmeyer flask instead of a volumetric flask. Use a graduated cylinder instead of a pipet for the transfer. Calibrate each piece of glassware. Instead of using a 1/50 dilution to make the solution, weigh out the material on a balance and transfer it directly to the volumetric flask.Explanation / Answer
Answer
1. The correct way is to transfer 20 ml of the given solution with a pippet into a volumetric flask Then increase the volume by adding water up to 1 litre mark.
The other method of transferring 1 ml of given solution using pippet is incorrect as pippet is caliberated in a way that it can accurately measure only 20 ml.
However the accuracy of this method can be improved if graduated cylinder (which can accurately measure 1 ml )is used instead of pippet.