Which are true for polarography? I Polarography is amperometry conducted with a dropping Hg electrode. II The diffusion current in the plateau region of the polarographic wave is proportional to the concentration of the analyte and is used for quantitative analysis. III The half-wave potential for maximum current is characteristic of a given analyte in a given medium and can be used for qualitative analysis for the analyte. IV Fresh Hg drops give reproducible results. V Polarography is used to primarily to study oxidations Hg may reduce when studying reductions. A.I, III, and IV B. II, III, and V C. I and V D. III, IV, and V E. II, III, and IV

Which are true for polarography? I Polarography is amperometry conducted with a dropping Hg electrode. II The diffusion current in the plateau region of the polarographic wave is proportional to the concentration of the analyte and is used for quantitative analysis. III The half-wave potential for maximum current is characteristic of a given analyte in a given medium and can be used for qualitative analysis for the analyte. IV Fresh Hg drops give reproducible results. V Polarography is used to primarily to study oxidations Hg may reduce when studying reductions. A.I, III, and IV B. II, III, and V C. I and V D. III, IV, and V E. II, III, and IV

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter17: Complexation And Precipitation Reactions And Titrations

Section: Chapter Questions

Problem 17.17QAP

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Which is correct for polarography? I-polarography is an amperometry method conducted with a dripping Hg electrode. II-The diffusion current in the plateau region of the polarographic wave is proportional to the concentration of the analyte and is used for quantitative analysis. III-The half-wave potential is characteristic of the analyte in a given environment and can be used for qualitative analysis. IV-fresh Hg drops provide reproducible results. V-polarography is primarily used to study oxidations, Hg can be reduced when studying reductions
Zinc is to be used as an internal standard for the polarographic analysis of thallium. A standard solution containing twice the concentration of zinc as Thallium has a diffusion current of 1.89 µA for Ti and 3.50 µA for Zn. A 10.0g alloy was dissolved in 500 mL, 25 mL of this solution was mixed with 25 mL of 1.0 x 10-3 M Zn 2+ solution. The diffusion currents of this final solution are 18.2µA for Tl+ and 14.5µA for Zn+. Calculate % Ti in the sample analysed
Please answer the following with complete solution. Thank you. A mixture placed in an Erlenmeyer flask comprises 6mL of silica gel and 40mL of a solvent containing, in solution, 100mg of a non-volatile compound. After stirring, the mixture was left to stand before a 10mL aliquot of the solution was extracted and evaporated to dryness. The residue weighed 12mg. Calculate the adsorption coefficient, K=CS/CM, of the compound in this experiment.
What are the advantages of a dropping-mercury electrode in polarography? Why is polarography used mainly to study reductions rather than oxidations?
Describe the principle and operation of anodic stripping voltammetry (ASV). How does it differ from adsorptive stripping voltammetry? What is the quantitative signal?
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The table shows a series of standard additions of Cu(II)to acidified water samples measured by anodic stripping voltammetry at a platinum electrode. The unknown and all standard additions were made up to the same final volume. 1. What chemical reaction occurs during the concentration stage of the analysis?2. What chemical reaction occurs during the stripping stage of the analysis?3. Plot absorbance as a function of the concentration of Cu (II) standard. Determine the equation of theline and the X intercept. Find the concentration of Cu(II) in the water.
Can electrogravimetry give total copper concentration and determine the concentration of specific species of either Cu(II) or Cu (I)? Why? And does it require a standard calibration curve? If not, how can the amount of analyte be determined?What about Polarography?
Please complete Table 2 and show the calculations for protein concentration and the concentration of the undiluted sample. a). Using Excel software, enter data from Table 1 to plot a standard curve (corrected average absorbance on Y-axis and protein concentrations on X-axis). The standard curve must contain correct labels on both axes. b). From the standard curve, obtain a best fit line and equation. c). Use the best fit equation and data from Table 2 to find the concentrations of proteins in sample A2-D2 and E1. [onto your plotted standard curve, indicate where A595 of A2-D2 and E1 are located] d). Calculate the concentrations of proteins in undiluted samples A to E. Thank you very much.
Question: What is the effect of pH on the reduction potential of a specific analyte in polarography?
kindly answer this problem and follow this format GIVEN REQUIRED SOLUTION and write regibly thank you so much For the adsorption of a substance A from aqueous solution by charcoal at25oC the freundlich constants are n=3.0 and k=0.50 for y in grams per gramand C in grams per liter. What weight of a W is adsorbed by 2 g of charcoalfrom 1 L of a solution containing originally 2 g of the substance?
An unknown cadmium(II) solution was analyzed. A 25.00-mL sample of the unknown solution produced a diffusion current of 1.86 mA. Following addition of a 5.00-mL aliquot of 0.00212 M Cd2+ standard solution to the unknown solution, a diffusion current of 5.27 mA was produced. A) What type of electroanalytical method was used? B) What type of calibration method was used? C) What is the molar concentration of Cd2+ in the unknown solution?