Hydroxy Naphthol Blue ACS 5g

Hydroxy naphthol blue is a synthetic azo dye and metal indicator that can be used to determine the concentration of calcium and magnesium in water:      Appearance: A bluish black crystalline powder  Uses: A calcium indicator and colorimetric reagent for alkaline earth metal ions pH range: In a pH range of 1213, the indicator is reddish pink in the presence of calcium ions and deep blue in the presence of disodium EDTA Preparation: To prepare hydroxy naphthol blue, you can dissolve 0.3 g in 100 mL of water, add 10 mL of 1 N sodium hydroxide volumetric solution, add 1.0 mL of calcium chloride solution, and dilute with water to 165 mL Endpoint: The endpoint of titration is indicated by a sharp color change from wine red to blue Hydroxy naphthol blue is used in complexometric titrations and metal titrations to determine the endpoint.