Discarded Penicillin Bottles for Constructing Reference Electrodes Penicillin bottles (size: ht. 3.5 om, diameter 2.3 m) o m be used for making convenient reference electrodes in potentiometric experiments. The adjoining drawing shows the construotion of the cdomel electrode. During the experiment, the electrode is placed in a. beaker containing the test solution and the second electrode. Electriod contact is established by a, strip of filter paper (easily replaced after use) ~oakedin potassium chloride solution. One end of the strip dips in the solution in the battle and the other in the test solution. The middle of the strip is held tightly between the mouth of the bottle and its stopper. The glass tube (T in the drawing) serves as a convenient handle. The electrode metal and the filling of the bottle may be changed to construct other reference electrodes such ss the silver-silver chloride electrode or the quinhydrone electrode.
G. RAMAMURTI K. RANGANATHAN L. R. GANESAN
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Journol of Chemical Education
