Question

A silver wire coated with AgCl is sensitive to the presence of chloride ion because of the half-cell reaction

AgCl(s) + e- --> Ag(s) + Cl-
E°AgCl = 0.2223 V

A student, wishing to measure the chloride ion concentration in a number of water samples, constructed a galvanic cell using the AgCl electrode as one half-cell and a copper wire dipping into 1.00 M CuSO4 solution as the other half-cell. In one analysis, the potential of the cell was measured to be 0.0624 V with the copper half-cell serving as the cathode. What was the chloride ion concentration (Ksp) in the water? (Take E°Cu2+ = 0.3419 V.)​

Answer 1

To measure chloride ion concentration, a galvanic cell is constructed using an AgCl electrode as one half-cell and a copper wire as the other half-cell. The potential of the cell is measured, and by subtracting the standard electrode potential of the AgCl half-cell from the measured potential, the chloride ion concentration can be calculated.

Step-by-step explanation:

To measure the chloride ion concentration in water samples, the student constructed a galvanic cell using an AgCl electrode and a copper wire dipping into a 1.00 M CuSO4 solution.

The potential of the cell was measured to be 0.0624 V with the copper half-cell serving as the cathode. The half-cell reaction at the AgCl electrode is AgCl(s) + e- → Ag(s) + Cl-. The standard electrode potential for the AgCl half-cell is 0.2223 V, and the standard electrode potential for the copper half-cell is 0.3419 V.

By subtracting the standard electrode potential of the AgCl half-cell from the measured potential of the cell, we can calculate the concentration of chloride ions (Ksp) in the water samples.