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Appearance
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A light, fine, white, amorphous powder
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Assay (as SiO2; on ignited basis)
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99.0 - 100.5%
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Identification
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To pass IP test
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Loss on ignition (on 0.2 g at 900°C; 2 hrs)
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Max 5.0%
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pH (in 1 gm in 30 ml water suspension)
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3.5 -5.5
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Chloride (Cl)
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Max 0.025%
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Arsenic (As)
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Max 0.0008%
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Solubility
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Practically insoluble in water and in mineral acds with the exception of hydrofluoric acid.Dissolve in hot solution of alkali hydroxides. When 1 g is shaken vigorously with 20 ml of carbon tetrachloride for 3 minutes; a transparent gel is produced
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