Background: This problem deals with preparation of a standard solution of KNO3. To do this, you might transfer an exact mass of solid KNO3 to a volumetric flask, dissolve the KNO3 in water, and then dilute the solution to the mark on the neck of the volumetric flask. In this example the volumetric flask you want to use contains some old KCl solution. You will need to discard the contents of the flask, then rinse it once or several times, before proceeding to prepare the standard solution of KNO3. Your final KNO3 solution will contain some residual chloride, depending on the the effectiveness of your rinsing procedure.

A 500-mL volumetric flask containing 0.526 M KCl is emptied and allowed to drain briefly, leaving 1.24 mL of liquid in the flask. The flask is then rinsed with 64.6 mL of distilled water and is then used to prepare a standard solution of KNO3. Compute the molar concentration of Cl- in the standard KNO3 solution if the flask is rinsed only one time with distilled water.

Assume that 1.24 mL of liquid remains in the flask each time it is emptied, and that this volume of rinse water remains in the flask prior to preparation of the KNO3 solution. Although in practice rinse volumes are generally approximate, for purpose of calculation please use the exact volumes indicated.