Question

3) In another experiment, a European brand low dose aspirin tablet was placed in a 500-ml volumetric flask and dissolved in 20 mL of 1.0M NaOH solution, the flask was then filled to the mark ( 500 mL) with deionized water. Using a pipette 50.0 mL of this solution was added into a 100-mL volumetric flask and diluted to the mark with FeCl3 solution. The absorbance recorded for the European aspirin tablet was 0.185. The following data was used for analysis. o Absorbance Vs Fe3+ SA Absorbance [Fe3+ SA) (M) O 0.113 3.0 x 10-4 0.239 6.0 x 10-4 0.331 9.0 x 10-4 0.482 1.2 x 10-3 0.587 1.5 x 10-3 y = 391.94x Abs 0 0.002 0.0005 0.001 0.0015 Concentration (M) Determine the mass in milligrams of salicylic acid in the European brand low dose aspirin tablet.

Answer 1

The acid Aspivin reacts with NaOH in an base reaction and nucleophilic subshitukas +2NaOH OHO -OHz Fost МОН, LOHI - OH डि from the stoichiometry of above equation conc. Of A = conc. of Fest_SA

The best fit equation for Calibrated Curve in y = 391.947 __y= Absorbance 2= [Fest_SA] 0.185 = 391694 x at ima 0:18 5 = 4.72x104m. 391.94 MT Fe3E-SA) = 4.72x104 m Salicystate gon AS setgi sabitaclia erand conc = (FeESAJ Salicylate gon A = 4.72x104m from the stoichiometry of equation ④ Atpirin cong = Salilyclate son conc. = 4.72 X1 4M 50 ml solution was diluted to 100 mL . Diluhien Fachar = 100 mL -9 somL -. conc. of original soo ml Solution = Dilution factor x conc. Of Aspirin indiluted solution.

conc. Of Aspirin in soome solution = 4:12X10 'mx2 = 9.44 x104m man of aspirin = conc. x volumex molar mall - = 944x1õtm X soo mL x 180:158%mol = 9.44x164461 x soox IQX x 180:1589/no1 = 850345.76x107 g 30.0859 = 85 ang also called Acetylsalicylic acid Aspirin is & Acetylsalicylic acid mall in the tablet = 85mg