0 votes
35 views
in Analytical Chemistry by (410 points)
How can the concentration of Cu(II) ions in a given solution be determined using cyclic voltammetry technique?

1 Answer

0 votes
by (490 points)
Cyclic voltammetry is an electrochemical technique that can be used to determine the concentration of various ions, including Cu II  ions, in a solution. The technique involves applying a potential to an electrode and measuring the resulting current as the potential is swept through a range of values. The current response provides information about the redox processes occurring at the electrode surface, which can be related to the concentration of the analyte of interest.To determine the concentration of Cu II  ions in a solution using cyclic voltammetry, follow these steps:1. Prepare the electrochemical cell: Set up a three-electrode system consisting of a working electrode  usually a glassy carbon electrode , a reference electrode  such as Ag/AgCl or saturated calomel electrode , and a counter electrode  such as a platinum wire . The working electrode is where the redox reactions of interest will occur, while the reference and counter electrodes help to control the applied potential and complete the electrical circuit, respectively.2. Prepare the solution: Prepare a solution containing the Cu II  ions of interest, along with a suitable supporting electrolyte  such as KCl or NaCl  to ensure adequate conductivity. The supporting electrolyte should not interfere with the redox reactions of the Cu II  ions.3. Perform the cyclic voltammetry experiment: Using a potentiostat, apply a potential to the working electrode and sweep the potential through a range that includes the redox potential of the Cu II /Cu I  couple  typically around +0.15 to +0.6 V vs. Ag/AgCl . Record the resulting current as a function of the applied potential. Repeat the potential sweep in the reverse direction to complete the cycle.4. Analyze the cyclic voltammogram: The resulting plot of current vs. potential  the cyclic voltammogram  will show a peak corresponding to the reduction of Cu II  to Cu I  and another peak corresponding to the oxidation of Cu I  back to Cu II . The peak current is proportional to the concentration of Cu II  ions in the solution, according to the Randles-Sevcik equation:ip =  2.69  10^5   n^1.5  A  D^0.5  C  ^0.5where ip is the peak current, n is the number of electrons transferred in the redox reaction  2 for Cu II /Cu I  , A is the electrode area, D is the diffusion coefficient of the Cu II  ions, C is the concentration of Cu II  ions, and  is the scan rate.5. Determine the concentration: To determine the concentration of Cu II  ions in the solution, you can either perform a calibration experiment using a series of solutions with known Cu II  concentrations to establish a relationship between peak current and concentration or use the Randles-Sevcik equation if the other parameters  A, D, and   are known.By following these steps and analyzing the resulting cyclic voltammogram, you can determine the concentration of Cu II  ions in a given solution using the cyclic voltammetry technique.
Welcome to Sarvan Science Q&A, where you can ask questions and receive answers from other members of the community.
...