Explanatory notes
… vanadium pentoxide, etc.). It is freed from impurities (nitrogen compounds, arsenical or seleniferous products, lead sulphate) by treatment with hydrogen sulphide or ammonium sulphide. Sulphuric acid is a … 28.06 and 28.08 , respectively). (b) Sulphur trioxide, hydrogen sulphide, peroxosulphuric (persulphuric) acids, …