need to find \"percentage of salicylic acid impurity -absorbance (y)-0.222 Deter
ID: 1046108 • Letter: N
Question
need to find "percentage of salicylic acid impurity -absorbance (y)-0.222 Determination of Salicylate via Reaction with Fe(lII) 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 R-09991_ 0 20 40 60 80 Concentration (mM) Figure 1, Calibration plot of Absorbance vs Concentration of Feall)-salicylate complex Steps Use this graph and the equation; to calculate the concentration of the complex for which you measured the absorbance. (y absorbance, solve for x) 2. x you calculated from step 1 is the concentration of the complex formed. It is formed via a 1:1 reaction between the salicylic acid impurity in your aspirin and the Fe(NO,)h added. Units are mM 3. From the mM concentration, you calculate the millimoles (multiply by the volume in L) and then the moles of salicylic acid and then the grams of salicylic acid. That is the amount of impurity of salicylic acid present in your aspirin. 4. (mass of Salicylic acid/mass of aspirina00 gives the % impurity.Explanation / Answer
y= 0.0129x+0.014
y (absorbance) = 0.222
x= (0.222-0.014)/0.0129 = 16.124
The concentration of complex is 16.124 mM. Ferric salicylate molecular weight is 467.187 g/mol.
Salicylic acid molecular weight 138.121 g/mol and Fe(NO3)3 molecular weight is 241.86 g/mol.
The reaction completes by 1:1 reaction between ferric salt and the salicylic acid.
Moles of salicylic acid = 16.124 mM = 0.016124 moles = 138.121 * 0.016124 = 2.2270 gm.
gms of ferric salt = 3.8997 gm.
mass of aspirin is to be supplied in the problem. and thus the % impurity is mass of salicyllic acid/mass of aspirin *100
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