8.) A 1.000 g sample of zinc metal is dissolved in 50 mL of 6 M HCI solution and dilutedto the mark in a 250 mL volumetric flask. A 25.00 mL portion is transferred to apolarographic cell and oxygen is flushed out. A polarogram in the range 0 – 1 V (vs. theHg-pool electrode) shows a wave at E1/2 = -0.65 V, id = 32.0 units of galvanometerdeflection. A 5.00 mL portion of 5.00 x 10-4 M CDC12 solution is added directly to thepolarography cell which already contains the Zn solution, oxygen is again flushed out,and a second polarogram is taken. The wave shows the same E1/2 but the id is 77.5units. Calculate the percent by weight of Cd impurity in the Zn metal. Note: Atomic weightof Cd is 112.4 g/mole.

Given that: Mass of Zn sample = 1.000 g Volume of the sample, V1 = 25 mL Diffusion current of the…

8.) A 1.000 g sample of zinc metal is dissolved in 50 mL of 6 M HCl solution and diluted to the mark in a 250 mL volumetric flask. A 25.00 mL portion is transferred to a polarographic cell and oxygen is flushed out. A polarogram in the range 0 - 1 V (vs. the Hg-pool electrode) shows a wave at E1/2 = -0.65 V, id = 32.0 units of galvanometer deflection. A 5.00 mL portion of 5.00 x 10-4 M CdCl2 solution is added directly to the polarography cell which already contains the Zn solution, oxygen is again flushed out, and a second polarogram is taken. The wave shows the same E1/2 but the id is 77.5 units. Calculate the percent by weight of Cd impurity in the Zn metal. Note: Atomic weight of Cd is 112.4 g/mole.

8.) A 1.000 g sample of zinc metal is dissolved in 50 mL of 6 M HCl solution and diluted to the mark in a 250 mL volumetric flask. A 25.00 mL portion is transferred to a polarographic cell and oxygen is flushed out. A polarogram in the range 0 - 1 V (vs. the Hg-pool electrode) shows a wave at E1/2 = -0.65 V, id = 32.0 units of galvanometer deflection. A 5.00 mL portion of 5.00 x 10-4 M CdCl2 solution is added directly to the polarography cell which already contains the Zn solution, oxygen is again flushed out, and a second polarogram is taken. The wave shows the same E1/2 but the id is 77.5 units. Calculate the percent by weight of Cd impurity in the Zn metal. Note: Atomic weight of Cd is 112.4 g/mole.

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter17: Complexation And Precipitation Reactions And Titrations

Section: Chapter Questions

Problem 17.31QAP

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