what are the disadvantages of non aqueous titrations

Answer 1

For some non-aqueous titrations see
http://en.wikipedia.org/wiki/Nonaqueous_titration

Disadvantages of non aqueous titrations depend on the solvent used.

Some have to be done in a fume cupboard because of the solvent.

For some solvents the evaporation rate of the solvent is rapid in a warm lab, so the concentrations of standards may be difficult to maintain.

Can be different and more expensive indicators to aqueous systems.

Some need to be done under an inert atmosphere, which is quite a skill to do.