NET_Chemical_Science_Solution

  Question:  The role of H 3 PO 4 in the estimation of Fe(II) with K 2 Cr 2 O 7 using diphenylamine sulphonate as indicator is to a)                    Avoid aerial oxidation of Fe(II) b)                   Reduce the electrode potential of Fe 3+   →   Fe 2+ c)                   Stabilizer the indicator d)                  Stabilize K 2 Cr 2 O 7 Answer : (b)  Reduce the electrode potential of Fe 3+   →   Fe 2+ Explanation For the titration of Fe 2+  with K 2 Cr 2 O 7 different indicators like diphenylamine, diphenylbenzidine and diphenylamine sulfonate may be used. All these indicators give green to violet co...