Dichromate titrations - oxidation reduction titrations
These are titrations where, potassium dichromate is utilized as an oxidising agent in acidic medium. The medium is organized acidic by the make use of dilute sulphuric acid. The potential reaction is
K2Cr2O7 + 4h2SO4 → K2SO4 + Cr2 (SO4)3 + 4 H20 + 3[O]
OR Cr2 O2-7 + 14 H+ + 6e- → 2 CR3+ + 7 H2O
The solution of potassium dichromate can be directly employed for titrations. It is generally used for the estimation of ferrous salts and iodides. In the titration of K2Cr2O7 versus ferrous salt either an external indicator that is potassium ferricyanide or an internal indicator that is diphenyl amine can be used.