Na2S2O3.5H2O M.W. 248.17
DESCRIPTION ................. white crystalline compound
SOLUBILITY .................. 10%aq. soln clear & colourless
ASSAY ....................... min 99.5%
pH(5% AQ SOLUTION) .......... 5.5-7.5
WATER INSOLUBLE MATTER ...... max 0.003%
CHLORIDE(Cl) ................ max 0.01%
IRON(Fe) .................... max 0.0005%
HEAVY METALS(Pb) ............ max 0.0005%
COPPER(Cu) .................. max 0.0005%
SULPHATE & SULPHITE(SO4) .... max 0.03%
SULPHIDE(S) ................. max 0.0001%
NITROGEN COMPOUNDS(N) ....... max 0.002%
POTASSIUM(K) ................ max 0.001%