Which is not an error associated with an incorrectly defined pH measurement? A) contact potential deviation-AgCl or Ag precipitates due to dilution of KCl or presence of reducing reagent B) alkaline fault - electrode responds to Na+ instead of H+ when [Na+] is low and [H+] is high C) acid error – the measured pH is higher than the actual pH because the glass is saturated with H+ and can no longer be protonated D) temperature – the pH meter is calibrated at different temperatures from the sample

Which is not an error associated with an incorrectly defined pH measurement? A) contact potential deviation-AgCl or Ag precipitates due to dilution of KCl or presence of reducing reagent B) alkaline fault - electrode responds to Na+ instead of H+ when [Na+] is low and [H+] is high C) acid error – the measured pH is higher than the actual pH because the glass is saturated with H+ and can no longer be protonated D) temperature – the pH meter is calibrated at different temperatures from the sample

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

ChapterA1: Evaluation Of Analytical Data

Section: Chapter Questions

Problem A1.23QAP

See similar textbooks

Similar questions

15- Which is not an error associated with an incorrectly defined pH measurement? a) contact potential deviation- AgCl or Ag precipitates due to dilution of KCl or presence of reducing reagent b) alkaline fault - electrode responds to Na+ instead of H+ when [Na+] is low and [H+] is high c) acid error – the measured pH is higher than the actual pH because the glass is saturated with H+ and can no longer be protonated d) temperature – pH meter calibrated at different temperatures from the sample
Indicate the option that is true:(1). An indicator electrode has an upper limit of measurement; That is, it does not serve as a precise analytical instrument when the concentrations of the analyte are very high.(2). Some electrodes take a long time to respond, but that is usually not an insurmountable drawback.(3). The representation of the potential of an indicator electrode against the analyte concentration is a straight line for analyte concentrations below a certain value.(4). For activities lower than the lower detection limit, the electrode always measures the same potential.
A bare silver wire electrode is dipped into a solution 0.05M in KNO3 (supporting electrolyte) and saturated in AgBr (Ksp = 5.0 x 10-13), and connected to the back of an mV/pH meter along with a saturated calomel reference electrode. Calculate the potential of the silver indicator electrode. Calculate the cell potential.
Which of the following statements is/are correct for coulometry? I. Coulometric methods count the electrons used in a chemical reaction to measure the analyte. II. Coulometry uses constant current or constant potential conditions. III. An advantage of coulometric methods is low reproducibility and a disadvantage is low sensitivity. IV. Coulometric titrations are constant potential methods. V. Constant potential methods using a three-electrode cell are more selective than constant-current methods. A). I, II and V B). I, II, IV and V C). I, III and IV D.) II, IV and V
Which of the following statements is/are correct for coulometry? I. Coulometric methods count the electrons used in a chemical reaction to measure the analyte. II. Coulometry uses constant current or constant potential conditions. III. An advantage of coulometric methods is low reproducibility and a disadvantage is low sensitivity. IV. Coulometric titrations are constant potential methods. V. Constant potential methods using a three-electrode cell are more selective than constant-current methods.
Traces of aniline can be determined by reaction with an excess of electrolytically generated Br2: C6H5NH2 + 3Br2 =====è C6H2Br3NH2 + 3H+ + 3Br- The polarity of the working electrode is then reversed, and the excess bromine is determined by a coulometric titration involving the generation of Cu(I): Br2 + 2Cu+ ===è 2Br- + 2Cu2+ Suitbale quantities of KBr and copper (II) sulfate were added to a 25.0 ml sample containing aniline (C6H5NH2). Calculate the mass in micrograms of C6H5NH2 in the sample from the accompanying data. Working electrode Functioning as Generation Time (min) with a constant current of 1.00 mA Anode 3.76 cathode 0.270
A series of solutions was prepared with pH varying from 1 to 13. Each solution contained 2.0mg/L fluoride and had the same ionic strength and temperature. The response of a fluoride ion selective electrode in each solution was recorded relative to a reference electrode. A graph of Ecell versus pH will curve: A.downwards at pH < 4.0 due to H+ interference B.downwards at pH < 4.0 due to OH- interference C.upwards at pH < 4.0 due to H+ interference D.upwards at pH < 4.0 due to OH- interference
Chemistry Potentiometry Topic Briefly discuss the following: 1.different types of membrane indicator electrode 2.how a pH glass electrode works 3.errors encountered in the use of pH electrode 4.contribution of other variables in the glass indicator potential
By how many volts will the potential of an ideal Mg2+ ion selective electrode (ISE) change if the electrode is removed from a 1.0 x 10-4 M solution of MgCl2 and placed in 1.0 x 10-3 M MgCl2? 28 mL of 0.1M Ce4+ is mixed with 50 mL of 0.05M Fe2+. The solution potential is monitored with a Pt indicator electrode and an Ag/AgCl reference electrode. Calculate the potential of the Pt electrode and the cell potential. An ion selective electrode for NO2- has the following values of Log k for the listed interferents. Interferent Logk F- -3.1 SO42- -4.1 I- -1.2 NO3- -3.3 Which ion…
An ion-selective electrode (ISE) produces voltage output (mV) proportional to solution pH. You have three standard pH solutions (4, 7, and 10). Assuming that pH 7 buffer solution is used together with pH 4 for calibration prior to measuring acidic solutions and together with pH 10 before measuring alkaline solutions, produce a flowchart of the calibration routine for a single pH ISE.
In a voltammogram, which of the following statements is correct 2 a. The limiting current i, is used for quantitative analysis b. The half-wave potential E₁/2 is used for quantitative analysis c. The limiting current i depends on the identity of the analyte d. The half-wave potential E1/2 dependens on the analyte concentration A 0.20 g sample of primary standard Na₂C₂O4 (134 g/mol) needed 37.22 mL of of KMnO4 solution to reach the end point. What is the molarity of KMnO4 reagent a. 0.14 M b. 0.016 M C. 0.65 M d. 0.0014 M In the glucose sensor, the component diffuses through the inner layer of the electrode is the J a. gluconic acid b. hydrogen peroxide c. glucose d. glucose oxidase
The following data were obtained with a cadmium-selective solid-state electrode. The ionic strength of each solution was 0.30 M, and the reference electrode was a saturated calomel electrode. Determine the concentration of the unknown cadmium ion in the sample. [Cd2+], M 1.00x10-1 8.75x10-3 1.00x10-3 3.16x10-5 3.16x10-6 Unknown E, V -0.115 -0.150 -0.175 -0.213 -0.242 -0.200