论文部分内容阅读
文献中有过两种用硫化物形式定量砷的方法。一种是用硫化氢使砷成为As_2S_5沉淀后再测定。此法需使砷成三价时才能得到良好的结果。另一法是在浓的冷盐酸溶液内,通入硫化氢使砷呈As_2S_5沉淀后,称重测定。此时五价砷常被部分地还原为三价状态。得到的As_2S_3。沉淀内因而总混有As_2S_5。及游离硫。产生沉淀的条件和溶液的浓度、温度等有关。如果在工作中能掌握沉淀的条件,用As_2S_3重量法测定砷,是可以得到正确
There are two methods of quantifying arsenic in the form of sulfides in the literature. One is the use of hydrogen sulfide to arsenic As2S_5 precipitation and then measured. This method requires arsenic trivalent to get good results. Another method is concentrated in cold hydrochloric acid solution, the introduction of hydrogen sulfide to arsenic was As2S_5 precipitation, the determination of the weight. At this point pentavalent arsenic is often partially reduced to the trivalent state. The obtained As_2S_3. As a result, the total amount of As_2S_5 in the pellet was mixed. And free sulfur. Precipitation conditions and the concentration of the solution, the temperature and so on. If in the work can grasp the conditions of precipitation, As 2 S 3 gravimetric determination of arsenic, can be correct