The Electrochemical Equivalent of Pure Silver-A Value of the Faraday

Oxygen-free high-purity samples were used in a precise determination of the electrochemical equivalent of silver. A comprehensive mass spectrometric analysis for impurities was performed. Our value agrees well with prior measurements of the same quantity at the National Bureau of Standards (NBS) by Craig and coworkers. We find the electrochemical equivalent of pure silver to be 1.1179648 mg $$ . Attached to this figure is an uncertainty whose random component (standard deviation of the mean of 8 determinations) is 9.5 × 10^-7 mg C^-1 (0.85 ppm). The root-sum-square of systematic uncertainties of known origin is 1.07 × 10^-6 mg C^-1 (0.96 ppm). The above value for the electrochemical equivalent of silver leads us to calculate the Faraday to be: F = 96486.33 (24) A · s · mol^-1 (2.5 ppm).