424 PRACTICAL ORGANIC CHEMISTRY covered beaker for about i hour in order to increase the size of the barium sulphate particles: if the solution tends to "bump," transfer it to a hot plate and keep it just below the boiling-point for about 2 hours. Then cool, filter and estimate the barium sulphate by any of the stan-dard methods, e.g., by filtering the liquid through a weighed Gooch crucible, washing the barium sulphate thoroughly with water, and then drying in an oven at about 130°. The value obtained for the percentage of sulphur should be within ± 0-2 of the theoretical value. NOTE, (i) Most sulphur compounds are completely oxidised if the tube is heated under the conditions described for the estimation of halogens. SuI-phonic acids and sulphones are more difficult to oxidise completely and the tube should be slowly heated to 300° and maintained at this temperature for at least 6 hours. The oxidation may be facilitated by adding a few crystals
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This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.