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What is the concentration of copper (II) ions in a given sample of wastewater using the polarographic method, given the obtained peak current is 2.5 mA and the standard potential of Cu2+ → Cu transformation is -0.34 V, working at a pH of 4.5 with a scan rate of 50 mV/s?

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ago by (490 points)
To determine the concentration of copper  II  ions in the wastewater sample using the polarographic method, we need to use the Randles-Sevcik equation:i_p =  2.69 x 10^5  * n^3/2 * A * D^1/2 * v^1/2 * Cwhere:i_p = peak current  2.5 mA n = number of electrons involved in the redox reaction  for Cu2+  Cu, n = 2 A = electrode area  we need this value to proceed D = diffusion coefficient of the analyte  we need this value to proceed v = scan rate  50 mV/s C = concentration of the analyte  Cu2+ ions First, we need to convert the scan rate from mV/s to V/s:v = 50 mV/s *  1 V / 1000 mV  = 0.05 V/sNow, we need the electrode area  A  and the diffusion coefficient  D  to proceed. These values are typically obtained from calibration experiments or literature sources. Assuming we have these values, we can rearrange the Randles-Sevcik equation to solve for the concentration  C :C = i_p / [ 2.69 x 10^5  * n^3/2 * A * D^1/2 * v^1/2]Once you have the values for A and D, you can plug them into the equation and calculate the concentration of copper  II  ions in the wastewater sample.

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