无水硫酸钠

无水硫酸钠 ? Sodium Sulfate contains ten molecules of water of hydration, or is anhydrous. It contains not less than 99.0 percent of Na2SO4, calculated on the dried basis. 硫酸钠含有10个水合分子，或者是无水化合物。按干燥后计算，它的Na2SO4 含量不低于99.0%。 Packaging and storage— Preserve in tight containers, preferably at a temperature not exceeding 30. – 贮存于密闭容器中，温度最好不超出30。 包装与贮存 Labeling— Label it to indicate whether it is the decahydrate or is anhydrous. 标签 – 标签上注明它是十水合物或是无水的。 Identification— A solution (1 in 20) responds to the tests for Sodium ，191， and for Sulfate ，191，. 鉴定 – 对钠<191>和硫酸盐<191>试验有响应的一种溶液。 Acidity or alkalinity— To 10 mL of a solution, containing the equivalent of 1.0 g of Na2SO4?10H2O in 20 mL of water, add 1 drop of bromothymol blue TS: not more than 0.50 mL of either 0.010 N hydrochloric acid or 0.010 N sodium hydroxide is required to change the color of the solution. 酸度或碱度 – 将10 mL溶液(含有1.0 g Na2SO4?10H2O)倒入20 mL的水中， 加入一滴溴百里蓝供试溶液:用于改变溶液颜色的0.010 N盐酸或0.010 N氢氧 化钠不超过0.50 mL。 Loss on drying ，731，— Dry at 105 for 4 hours: the decahydrate loses between 51.0% and 57.0% of its weight, and the anhydrous form loses not more than 0.5% of its weight. 干燥失重<731> - 在105的条件下干燥4个小时:十水合物的损失在其重量的 51.0% 和 57.0%之间，无水形态的损失不超过其重量的0.5%。 Chloride ，221，— A portion equivalent to 1.0 g of Na2SO4?10H2O shows no more chloride than corresponds to 0.30 mL of 0.020 N hydrochloric acid (0.02%). 氯化物<221> - 1.0 g Na2SO4?10H2O中的氯化物不高于0.30 mL的0.020 N盐 酸(0.02%)中的氯化物。 Heavy metals ，231，— Dissolve a portion containing the equivalent of 2.0 g of Na2SO4?10H2O in 10 mL of water, add 2 mL of 0.1 N hydrochloric acid, then add water to make 25 mL: the limit is 0.001%. 重金属<231> - 将相当于2.0 g Na2SO4?10H2O的份量倒入10 mL的水中，加入 2 mL的0.1 N盐酸，然后加水至25 mL:限度是0.001%。 Assay— Weigh accurately a portion of Sodium Sulfate, equivalent to about 400 mg of anhydrous sodium sulfate, dissolve in 200 mL of water, and add 1 mL of hydrochloric acid. Heat to boiling, and gradually add, in small portions and while constantly stirring, an excess of hot barium chloride TS (about 8 mL). Heat the mixture on a steam bath for 1 hour, collect the precipitate of barium sulfate on a tared filtering crucible, wash until free from chloride, dry, ignite, and weigh. The weight of the barium sulfate so obtained, multiplied by 0.6086, represents its equivalent of Na2SO4. 含量测定 – 将经过精确称量的一部分硫酸钠(相当于大约400 mg的无水硫酸 钠)溶解在200 mL的水中，加入1 mL的盐酸。加热至沸腾，在不断搅拌下逐渐 少量加入超量的热氯化钡供试溶液(大约8 mL)。在蒸汽浴中加热该混合物1 小时，在配衡过滤坩埚中收集硫酸钡的沉淀物，清洗直至除去氯化物，干燥、燃 ，即是Na2SO4的相等物。 烧并称量。将得出的硫酸钡重量乘以0.6086