To determine the concentration of chloride ions in the seawater sample, we can use the Nernst equation, which relates the potential difference of an electrochemical cell to the concentration of the ions involved. The Nernst equation is given by:E = E - RT/nF * ln Q where:E = the measured potential difference 0.64 V E = the standard potential of the silver-silver chloride electrode 0.22 V R = the gas constant 8.314 J/molK T = the temperature in Kelvin 25C = 298.15 K n = the number of electrons transferred in the redox reaction 1 for Ag/AgCl F = Faraday's constant 96,485 C/mol Q = the reaction quotient, which is equal to [Cl-] in this caseFirst, we need to solve for Q:0.64 V = 0.22 V - 8.314 J/molK * 298.15 K / 1 * 96,485 C/mol * ln Q Rearrange the equation to isolate ln Q :ln Q = 0.64 V - 0.22 V * 1 * 96,485 C/mol / 8.314 J/molK * 298.15 K ln Q 1.931Now, we can find the concentration of chloride ions by taking the exponent of both sides:Q = e^1.931 6.9Since Q = [Cl-], the concentration of chloride ions in the seawater sample is approximately 6.9 M.