Codes & Standards - Purchase
ISO 2833:1973
Sodium fluoride for industrial use -- Determination of fluorine content -- Modified Willard-Winter method
SKU: iso_007830_102476
Published by ISO
Publication Year 1973
1 Edition
5 pages
Product Details
The principle consists in separation of the fluorine from a test portion by distillation with sulphuric acid or perchloric acid. Titration with thorium nitrate solution using sodium alizarinsuphonate and methylene blue as indicators. Alternatively the thorium nitrate titration may be carried out using sodium alizarinsuphonate alone as indicator, the end-point being determined spectrophotometrically under carefully defined conditions. The absorbance at a wavelength of 525 nm shall reach the arbitrary value of 0.6. Has also been approved by the IUPAC.