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11 Nov 2019
When a silver electrode is polarized anodically in a solution containing a halide ion, the following reaction occurs: where X- denotes Cl, Br, or I. Suppose that a silver electrode is polarized anodically in the controlled-potential electrolysis of a solution initially containing 0.0319 MBr. What is the minimal potential (versus SHE) at which the silver anode must be polarized to ensure an accuracy (completeness of deposition of AgBr(s)) of at least 99.9% for the deter-mination of Br. (a) AgBr(s) + Ag(s) + Br ; Eo= +0.073 V vs. SHE (b) Suppose that controlled-potential coulometry with a silver anode is to be used for the separation and analysis of a mixture of 0.0400 M Cl and 0.0500 MI. Within what range of potentials (versus SHE) must the silver anode be main- tained to ensure the deposition of at least 99.9% of the 1, as Agl(s), without removal of any Cl- from the sample solution? After removal and quantitative determination of the I, the potential of the silver anode can be readjusted and the electrolysis can be resumed- without the need to remove the earlier coating of Agl(s)--to deposit and determine at least 99.9% of the Cl-as AgCl(s). To what new potential (versus SHE) must the silver anode be adjusted for the determina- tion of Cl-? AgCl(s) + Ag(s) + Cl- . E oã¼+0.222 V vs. SHE e Agl(s) + e Ag(s) + I- ; Eo=-0. I 5 1V vs. SHE
When a silver electrode is polarized anodically in a solution containing a halide ion, the following reaction occurs: where X- denotes Cl, Br, or I. Suppose that a silver electrode is polarized anodically in the controlled-potential electrolysis of a solution initially containing 0.0319 MBr. What is the minimal potential (versus SHE) at which the silver anode must be polarized to ensure an accuracy (completeness of deposition of AgBr(s)) of at least 99.9% for the deter-mination of Br. (a) AgBr(s) + Ag(s) + Br ; Eo= +0.073 V vs. SHE (b) Suppose that controlled-potential coulometry with a silver anode is to be used for the separation and analysis of a mixture of 0.0400 M Cl and 0.0500 MI. Within what range of potentials (versus SHE) must the silver anode be main- tained to ensure the deposition of at least 99.9% of the 1, as Agl(s), without removal of any Cl- from the sample solution? After removal and quantitative determination of the I, the potential of the silver anode can be readjusted and the electrolysis can be resumed- without the need to remove the earlier coating of Agl(s)--to deposit and determine at least 99.9% of the Cl-as AgCl(s). To what new potential (versus SHE) must the silver anode be adjusted for the determina- tion of Cl-? AgCl(s) + Ag(s) + Cl- . E oã¼+0.222 V vs. SHE e Agl(s) + e Ag(s) + I- ; Eo=-0. I 5 1V vs. SHE