A Versatile Cell for
1. Feldman and A. T. Kuhn
Leesona Moos laboratories Great Neck, New York
Electrochemical Measurements
M o s t electrochemical measurements of electrode potentials, corrosion processes, and electroorganic reactions, are made in specially designed multicompartment cells. This article describes a cell in which the components are either stock items or else readily made. The components are interchangeable; breakages can thus be immediately rectified. The use of Vicor components affords greater corrosion resistance. The basic component of the cell is a five-necked 500ml Pyrex flask, with 24/40 necks. The study electrode is held in the center neck with a rubber or Teflon D
B
A
C
E l .
Cell for eledrochemical meorurementr. A, study electrode; 8, par bubbler; C, reference electrode; D, counter electrode; E, water racketed condenser; F, thermometer.
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Journol of Chemical Edumfion
stopper. The reference electrode is contained in a separate compartment formed by a Pyrex 24/40 Ground Joint tube. The bottom of this tube is drawn out to form a Luggin capillary which, when in position, will virtually touch the study electrode. The top of the tube is removed about 1 in. ahove the joint, thus permitting the inertion of a calomel or similar reference electrode. The counter electrode is also mounted in a compartment similar to the one described above. In this case, however, a glass frit is sealed to the end of the tube to prevent bubbles formed at the counter electrode from escaping into the hulk of the electrolyte. The gases so formed are, instead, vented through a small hole in the Pyrex tube ahove the level of the solution. A thermometer and a gas bubbler are inserted in the two remaining necks of the flask. The bubbler may he used to purge the electrolyte solution with helium or to saturate it with oxygen or other gases. A magnetic stirrer may he used in the cell. For diffusion studies a rotating wire electrode is inserted through the center neck using the Teflon stopper as a hearing. While the ahove arrangement is satisfactory a t ambient temperatures, minor modifications enable the cell to he used a t higher temperatures. A cell thus modified has provided reproducible data with phosphoric acid a t 200°C over periods of several days. The thermometer is replaced by a water jacketed condensor. The thermometer may be mounted inside the condensor. Alternatively, flasks are available with an additional 10/30 neck for separate fitting of the thermometer (see figure). The cell is heated with a mantle and a thermoregulator, which in draft free conditions enable the temperature to be controlled +2"C.
