6) Voltammetry - In linear scan voltammetry, the diffusion current is proportional to the concentration of the species being reduced. In one experiment 250.00 mL of a 6.00 x 104 M Cd²+ (aq) solution was analyzed using a mercury electrode. The voltammetry scan from -0.6 to-1.2 V took 3.40 minutes to complete. The diffusion current for the reduction of Cd²+ at the mercury electrode was 14.0 µA (14.0 x 10° A). Cd²+ (aq) + 2 e ----> Cd (s) a) How many mmol Cd²+ were initially present? (in the 250.00 mL solution) b) Using the current and time, calculate the charge (coulombs) delivered to the solution. c) How many mmol of Cd²+ were reduced (deposited) during the analysis by this current? d) Using the answers from parts (a) and (c), calculate the percentage of Cd2+ that was reduced in the analysis. e) A second solution of unknown Cd²+ concentration was analyzed similarly and the diffusion current was only 10.2 µA. What is the Cd2+ for the unknown solution? (Use current is proportional to concentration)

6) Voltammetry - In linear scan voltammetry, the diffusion current is proportional to the concentration of the species being reduced. In one experiment 250.00 mL of a 6.00 x 104 M Cd²+ (aq) solution was analyzed using a mercury electrode. The voltammetry scan from -0.6 to-1.2 V took 3.40 minutes to complete. The diffusion current for the reduction of Cd²+ at the mercury electrode was 14.0 µA (14.0 x 10° A). Cd²+ (aq) + 2 e ----> Cd (s) a) How many mmol Cd²+ were initially present? (in the 250.00 mL solution) b) Using the current and time, calculate the charge (coulombs) delivered to the solution. c) How many mmol of Cd²+ were reduced (deposited) during the analysis by this current? d) Using the answers from parts (a) and (c), calculate the percentage of Cd2+ that was reduced in the analysis. e) A second solution of unknown Cd²+ concentration was analyzed similarly and the diffusion current was only 10.2 µA. What is the Cd2+ for the unknown solution? (Use current is proportional to concentration)

Principles of Instrumental Analysis

7th Edition

ISBN:9781305577213

Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Publisher:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Chapter25: Voltammetry

Section: Chapter Questions

Problem 25.1QAP

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