(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

Calculate the diffusion coefficient (cm2/s) of ferricyanide if cyclic voltammograms conducted on a solution of 1 mM KClO4 + 5 mM K4Fe(CN)6 at scan rates of 1, 2, 5, 10, 20, and 50 mV/s, resulted in peak currents of 76, 100, 175, 243, 348 and 552 mA. The electrode used for the experiment had been modified with a polymeric coating an effective area of 0.56 cm^{2}.

2. Relevant equations

i_{pc}=(269000)n^{3/2}AD^{1/2}C v^{1/2}

A=0.56 cm^{2}

n=1

C= 0.000005 mol/cm^{3}

3. The attempt at a solution

I ploted the i_{pc}vs. v^{1/2 }and found the slope of the line which was approx. 76.747

i_{pc}/v^{1/2}= 76.747

Isolating for D =[76.747/((269000)n^{3/2}AC)]^{2}

=[76.747/((269000)1^{3/2}0.56x0.000005)]^{2}

= 10 382.51

which is clearly wrong since the theoretical value of D is 7.6 x 10^{-6}

Can anyone point out my mistake? I have a feeling it's with the concentration though I'm not quite sure...

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# Homework Help: Cyclic Voltammetry

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