Some triphenylmethane dyes as redox indicators in the titration of antimony(III) with cerium(IV) sulphate.
Erioglaucine A, Eriogreen B, Patent Blue and Xylene Cyanol FF work satisfactorily for the titration of Sb(III) with Ce(IV) in 1-2N sulphuric acid medium with iodine as catalyst. In hydrochloric acid medium the colour of the oxidized dye is very evanescent but is very much improved in intensity and stability by the addition of manganese(II) sulphate; no catalyst is needed.
Rao
G G
GG
Department of Chemistry, Andhra University, Waltair, India.
Viswanath
S G
SG