Principles of Instrumental Analysis
7th Edition
ISBN: 9781305577213
Author: Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher: Cengage Learning
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Chapter 14, Problem 14.21QAP
Interpretation Introduction
Interpretation:
The formation constant for the process
Concept introduction:
The Beer-Lambert Law is:
A − absorbance
l − length of the solution light passes through (cm)
c − concentration of solution (mol/L)
Formation constant is the equilibrium constant for the formation of complex in a solution. This is also known as stability constant.
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A 1.000-g sample containing bromide was dissolved in sufficient water to give 100.0 mL. A 50.00 mL aliquot was measured and after acidification, silver nitrate was introduced to precipitate AgBr, which was filtered, washed, and then dissolved in an ammoniacal solution of potassium tetracyanonickelate(II):
Ni(CN)42- + 2AgBr(s) → 2Ag(CN)2- + Ni2+ + 2Br-
The liberated nickel ion required 11.70 mL of 0.002146 M EDTA
The other 50.00 mL remaining solution was also analyzed for its Br- content by potentiometry using a metallic electrode of the second kind.
Ecell recorded in running the solution using the potentiometric set-up was Ecell = 0.0286 V. (E0Ag/AgBr = 0.095 V)
g) Compute for Eind.
h) Compute pBr in the 50.00 mL aliquot.
i) Compute for % NaBr ( in the potentiometric technique).
j) Calculate the error between the obtained % NaBr fr the EDTA titration technique and the % NaBr from the potentiometric technique.
A 1.000-g sample containing bromide was dissolved in sufficient water to give 100.0 mL. A 50.00 mL aliquot was measured and after acidification, silver nitrate was introduced to precipitate AgBr, which was filtered, washed, and then dissolved in an ammoniacal solution of potassium tetracyanonickelate(II):
Ni(CN)42- + 2AgBr(s) → 2Ag(CN)2- + Ni2+ + 2Br-
The liberated nickel ion required 11.70 mL of 0.002146 M EDTA.
Calculate mmol Ni in the 50.00 mL aliquot.
Calculate mmol Br- in the 50.00 mL aliquot.
Calculate the percentage of NaBr (102.894) in the 1.000 g sample.
A 1.000-g sample containing bromide was dissolved in sufficient water to give 100.0 mL. A 50.00 mL aliquot was measured and after acidification, silver nitrate was introduced to precipitate AgBr, which was filtered, washed, and then dissolved in an ammoniacal solution of potassium tetracyanonickelate(II):
Ni(CN)42- + 2AgBr(s) → 2Ag(CN)2- + Ni2+ + 2Br-50.00 mL remaining solution was analyzed for its Br- content by potentiometry using a metallic electrode of the second kind.
a) Write the cell notation of the potentiometric set-up with SCE as the reference electrode.
b) Write the Nernst equation that describes the indicator electrode set-up.
Ecell recorded in running the solution using the potentiometric set-up was Ecell = 0.0286 V. (E0Ag/AgBr = 0.095 V)
c) Compute for Eind.
d) Compute pBr in the 50.00 mL aliquot.
e) Compute for % NaBr ( in the potentiometric technique).
Chapter 14 Solutions
Principles of Instrumental Analysis
Ch. 14 - Prob. 14.1QAPCh. 14 - A 0.4740-g pesticide sample was decomposed by wet...Ch. 14 - Sketch a photometric titration curve for the...Ch. 14 - Prob. 14.4QAPCh. 14 - Prob. 14.5QAPCh. 14 - The accompanying data (1.00-cm cells) were...Ch. 14 - A 3.03-g petroleum specimen was decomposed by wet...Ch. 14 - Prob. 14.8QAPCh. 14 - Prob. 14.9QAPCh. 14 - The acid-base indicator HIn undergoes the...
Ch. 14 - Prob. 14.11QAPCh. 14 - Prob. 14.12QAPCh. 14 - Copper(II) forms a 1:1 complex with the organic...Ch. 14 - Aluminum forms a 1:1 complex with...Ch. 14 - Prob. 14.15QAPCh. 14 - Prob. 14.16QAPCh. 14 - Prob. 14.17QAPCh. 14 - Prob. 14.18QAPCh. 14 - Prob. 14.19QAPCh. 14 - Given the Information that...Ch. 14 - Prob. 14.21QAPCh. 14 - Mixing the chelating reagent B with Ni(II) forms...Ch. 14 - Prob. 14.23QAP
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