Abstract
In this work an experimental accuracy to give results which
can be taken as accurate to better than one part in 1000 has
been aimed at, and, in order to make some comparisons between
cations, in the absence of all the relevant salt conductance
data, the work has been carried out using nitrate solutions. A
method using an "autogenic" boundary (6,34) has been devised
as this avoided the enormous practical problem which would
have been created in attempting to set up a "sheared"
boundary (35). Mercury was chosen as the anode metal as it
can be poured into the sealed tube of the transference cell,
freezes to form a good seal in the tube and electrolyses to
form the soluble mercuric nitrate which acts as the indicator
electrolyte. Silver was the other metal which was seriously
considered for the purpose but it was found to be difficult
to obtain a neat silver to glass fit when the system was to be
used some 60 to 80 C. degrees below the ambient temperatures,
as the two materials have different coefficients of
expansion.
With experience which has been gained in the course of
this work it is hoped that a much more accurate determination
of the transference number of the K+ ion in potassium iodide
solution in liquid ammonia will be possible to provide a standard upon which accurate single ion conductance data can
ultimately be based.
