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Description
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A fine, amorphous, impalpable, pink or reddish brown powder.
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Identification 'A'
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Gives the reactions of zinc salts
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Identification 'B'
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A reddish colour is produced
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Acid insoluble substances
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NMT 1% w/w
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Alkaline substances
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NMT 0.2 ml of 0.05 M sulphuric acid is required to decolorise it.
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Water soluble dyes
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The filtrate is colourless
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Arsenic
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Less than 8 ppm
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Lead
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The solution remains clear for 5 minutes.
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Calcium
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The solution remains clear for 2 minutes.
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Soluble barium salts
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The solution remains clear for 5 minutes.
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Chlorides
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Less than 750 ppm
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Sulphates
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Less than 0.6%
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Loss on ignition (at 900°C)
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NMT 2.0%
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Microbial contamination
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Free from Staphylococcus aureus and Pseudomonas aeruginosa
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Assay (on ignited basis)
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NLT 98.0% and NMT 100.5% of ZnO
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