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The Chemical Educator
ISSN: 1430-4171 (electronic version)
Abstract Volume 25
(2020) pp 45-49
Using an Electrolytic Capacitor to Deliver Charge to an
Electrolysis Cell: An Interdisciplinary Undergraduate Laboratory Titration
Experiment
Dawson Dooley‡, Abiye Seifu‡, Jaimie
Gonzalez†, Shaquithea Harris†, Jasmine Bohannon†,
Rajeev B Dabke*,†
†Department of Chemistry, Columbus State University, Columbus, Georgia 31907, dabke_rajeev@columbusstate.edu; ‡Department of Earth and Space Sciences, Columbus State University, Columbus, Georgia 31907 Received December 18, 2019. Accepted February 19, 2020.
Published: 3 March 2020
Abstract. A
feasible use of an electrolytic capacitor to deliver charge to an electrolysis
cell and quantify the product of electrolysis of water is presented. A DC power
source was used to charge an electrolytic capacitor. The charge was delivered
to an electrolysis cell. Electrolysis of water in the cathode and anode
compartments produced OH-(aq) and H+(aq) ions, respectively. A
known volume of vinegar was added to the cathode compartment. Electrolytically
produced OH-(aq)
neutralized the acid present in vinegar. The charging-discharging cycles were
repeated and the pH was monitored after each cycle. The percentage of acetic
acid (5.27%) in vinegar was determined from the equivalence point. Electrolytic
titration was performed for larger volumes of vinegar and the equivalence point
was determined from a visual color change of an indicator. The percentage of
acetic acid was 4.82%. The percentage of acetic acid determined from the
proposed electrolytic titrations was consistent with the manufacturer’s label
and volumetric titration (5%). Two interdisciplinary laboratory titration
experiments for the determination of acetic acid in household vinegar are
presented. Consistency of the quantity
of charge delivered to the electrolysis cell was independently tested for different
charging voltages. The total charge required to reach the equivalence point of
neutralization of standard KHP was constant (0.392 C) and consistent with the
expected charge (0.390 C).
Key Words: Laboratories and Demonstrations; physical chemistry; electrochemistry; electrolysis; titration; electrolytic capacitors; interdisciplinary learning
(*) Corresponding author. (E-mail: dabke_rajeev@columbusstate.edu)
Article in PDF format (212 KB) HTML format
Supporting Materials:
Notes and additional information for instructors, student handout
for two experiments, and post-laboratory exercise with key.
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