4-Nitro-2-Aminophenol-2- Sulfonic Acid is a kind of centrifuged material and is soluble in di-alkaline. 4-Nitro-2-Aminophenol-2- Sulfonic Acid contains insoluble matters in a range of less than 0.2%.4-Nitro-2-Aminophenol-2- Sulfonic Acid is offered in pinkish brown coloured appearance. 4-Nitro-2-Aminophenol-2- Sulfonic Acid is free from any kind of chlorination.