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Molecular formula: Na2S2O3·5H2O
Molecular weight: 248.18
Properties: Colorless crystal or white particle, no odor. Weathering in the dry air. Soluble in water and insoluble in ethyl alcohol. Density is 1.729. It loses water of crystallization at 100℃.
Uses: As analytical reagent such as oxidation-reduction titration agent and reducing agent. As mordant and fixing agent.
Standard:
| Specifications/item |
AR
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CP
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Assay(Na2S2O3·5H2O)/%
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≥99.0
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≥98.5
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PH value (50g/L solution,25℃)
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6.0~7.5
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6.0~7.5
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Clarity test
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Qualified
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Qualified
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Water insoluble matter/%
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≤0.005
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≤0.01
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Chloride(Cl) /%
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≤0.02
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－
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Sulfate and sulfite(SO4) /%
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≤0.05
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≤0.1
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Sulfide(S) /%
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≤0.000 25
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≤0.000 5
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Total nitrogen(N) /%
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≤0.005
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－
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Magnesium (Mg) /%
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≤0.001
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－
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Calcium (Ca) /%
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≤0.003
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≤0.005
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Iron (Fe) /%
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≤0.000 5
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≤0.001
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Heavy metal (Pb) /%
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≤0.000 5
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≤0.001
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Packing: Plastic woven bag lined with plastic bag, kraft bag, carton or fiber drum, net weight is 25kg.
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