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Appearance
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White granules or powder
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Solubility
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Practically completely soluble in mineral acids and insoluble in water
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Identification 'A' & 'B'
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Passes IP test
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Acid insoluble matter
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Max 1.0%
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Alkaline substances
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If red colour is produced, NMT 0.2 ml of 0.05M sulphuric acid should be required to decolourise it
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Water soluble dyes
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The filtrate should be colourless
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Ethanol soluble dyes
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The filtrate should be colourless
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Arsenic (As)
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Max 8.0 ppm
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Lead (Pb)
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The solution should remains clear after 5 minutes
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Calcium (Ca)
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The solution should remains clear
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Soluble barium salts
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The solution should remains clear
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Chlorides
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NMT 750 ppm
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Sulphates
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NMT 0.6%
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Loss on ignition
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Max 2.0% (at 900°C on 2.0 gm of sample)
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Microbial contamination
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1 gm should be free from staphylococcus aureus and Pseudomonas aeruginosa
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Assay (as ZnO; on ignited basis)
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98 - 100.5%
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