5-Sulfosalicylic acid

2 -hydroxy-5 -sulfo- benzoic acid ( IUPAC)

• C7H6O6S (anhydrous)
• C7H6O6S · 2 H2O

• 97-05-2 (anhydrous)
• 5965-83-3 (dihydrate )
• 304851-84-1 ( hydrate)

White crystal with a slightly pungent odor

• 218.187 g · mol -1
• 254.22 g · mol -1 ( dihydrate)

Fixed

0.8 g · cm -3

105-109 ° C. (dihydrate )

Readily soluble in water

Risk

Template: Infobox chemical / molecular formula search available

5 -sulfosalicylic acid is a chemical compound selected from the group consisting of sulphobenzoic acid derivatives. It is a white crystalline solid with a slightly pungent odor.

Use

5 -sulfosalicylic acid is used as an indicator in the complexometric, preferably for the determination of iron (III) in an acidic medium (pH ≈ 2.5 ). The determination of the iron is similar to the use of tiron. It changes color from red to yellow.

Application

Iron (III) is 5 -sulfosalicylic acid a red chelate. To allow a complete determination of the iron, if present, iron (II) to be oxidized to iron ( III). By titration with EDTA, the iron is pushed out of the chelate; determining ends at the disappearance of the red color, with the envelope can be slow sometimes. The determination is relatively selective. Manganese, cobalt, nickel, copper and zinc do not interfere. Since the alkaline earth metals are titrated with EDTA in the weakly basic buffered medium, they also do not interfere.

If it is mixed iron (II ) salts with 5- sulfosalicylic acid and NH4OH solution, we obtain a yellow complex which can be measured photometrically at 405 nm.