Studies on metallochromic indicators--I. Pyrocatecholphthalein as metallochromic indicator.
Pyrocatecholphthalein has been used as a metallochromic indicator for the direct complexometric titrations of a number of metal ions with EDTA, both in acidic and in alkaline medium. Th, Bi(III), Ba, Sr, Ca, Mg, Mn(II), Pb(II), Cu(II), Cd, Ni, Co(II) and Zn have been successfully titrated. In comparison with Pyrocatechol Violet, this dyestuff gives sharper end-points when the titrations are done at high pH.
Singhal
G K
GK
Chemistry Department, Rajasthan University, Jaipur, India.
Tandon
K N
KN