Page 26 - Pharmaceutical Analytical Chemistry II - Pharm D Clinical- 07-PA202

▪ It is considered as an ideal redox indicator:
1. It reacts rapidly and reversibly
2. Its color change is sharp
3. Its solutions are stable

Diphenylamine sulfonic acid

HSO3 H
N

Diphenylamine sulfonic acid

▪ Sodium salt of this indicator is used to prepare aqueous solution
▪ Indicator reaction,

(E0 = 0.8 V)

▪ Color change is sharper, from colorless --- green----- violet
▪ It is used in titrations with st. Cr2O72- solution

Potentiometric end point detection

(refer to practical book)

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