Palladium(II) forms an intensely colored complex at pH 3.5 with arsenazo III at 660 nm.33 A meteorite was pulverized in a ball mill, and the resulting powder was digested with various strong mineral acids. The resulting solution was evaporated to dryness, dissolved in dilute hydrochloric acid, and separated from interferents by ion-exchange chromatography. The resulting solution containing an unknown amount of Pd(II) was then diluted to 50.00 mL with pH 3.5 buffer. Ten-milliliter aliquots of this analyte solution were then transferred to six 50-mL volumetric flasks. A standard solution was then prepared that was 1.00 × 10-5 M in Pd(II). Volumes of the standard solution shown in the table were then pipette into the volumetric flasks along with 10.00 mL of 0.01 M arsenazo III. Each solution was then diluted to 50.00 mL, and the absorbance of each solution was measured at 660 nm in 1.00-cm cells.

       

Volume Standard Solution, mL	A660
0.00	0.216
5.00	0.338
10.00	0.471
15.00	0.596
20.00	0.764
25.00	0.850

(a) Enter the data into a spreadsheet, and construct a standard-additions plot of the data.

(b) Determine the slope and intercept of the line.

(c) Determine the standard deviation of the slope and of the intercept.

(d) Calculate the concentration of Pd(II) in the analyte solution.

(e) Find the standard deviation of the measured concentration.