  In this work, the Quasi-Random Lattice (QRL) model is summarized and
critically discussed, in order to outline its potentialities and limitations,
in perspective of future developments. QRL primarily focuses on the mean
activity coefficient of ionic solutions, the model having first been developed
in order to provide practical equations, able to involve a minimal number of
unknown or unpredictable quantities. QRL at present depends on one adjustable
parameter (at given pressure and temperature), experimentally known for many
common salts either symmetric or asymmetric, and corresponding to a
well-defined concentration, which also sets the upper limit of applicability of
the model. For aqueous electrolytes, the concentration-parameter ranges from 1
M to 8 M (about). In the following it will be seen that, although belonging to
the class of simplified approaches, QRL can provide very interesting results
since its simple parametrisation is more significant, from a theoretical point
of view, than so far recognized. A general overview of the QRL theory will
first be presented. Then, some preliminary results will be discussed, in
particular concerned with volumetric and thermal properties of electrolyte
solutions.
