back titration

[judy159]

what is advantage of back titration? I only now it is faster then direct titration.
is there any more reason?

[thushan]

1) If the alternative was titrating a strong acid with a weak base.
2) If the substance to be analysed was volatile.
3) If the substance to be analysed was a base that is only soluble in acidic conditions (in which you'd add an excess of HCl), eg. CaCO3, or an acid that is only soluble in basic conditions (in which you'd add an excess of NaOH).