4) An unknown concentration of NiSO4 solution is to be determined by colorimetric analysis using a…

4) An unknown concentration of NiSO4 solution is to be determined by colorimetric analysis using a spectrophotometer. The standard solutions are prepared as the following: 2.00 mL (the same procedures for 3.0 mL, 4.00 mL, 6.00 mL, 7.00 mL) of the stock solution of 1.00 M NİSO4 is transferred into a 25-mL volumen flask and diluted by adding distilled water to the mark line. The spectrophotometer is calibrated at the wavelength of 635 nm. The absorbance (A) readings and the concentrations of these standard solutions are tabulated Volumes of Concentrations of Absorbance the Stock the standard Solution (mL) 2.00 3.00 4.00 6.00 7.00 solutions (M) 0.132 0.198 0.264 0.390 0.458 a) Calculate the concentrations of the standard solutions and complete the column 2 in the above table riables) versus the absorbance readings (dependen variables) and draw the best straight-line possible. c) If the unknown absorbance is 0.250, what is the concentration of the unknown?