【单选题】称取含有As 2 O 3 和As 2 O 5 的试样0.5000g,溶解后,在弱碱性溶液中用c(1/2I 2 )=0.1000mol/LI 2 溶液滴定至终点,消耗30.00mL。将此溶液用HCl调制酸性,加入过量KI,析出的I 2 用c(Na 2 S 2 O 3 )=0.3000mol/L的Na 2 S 2 O 3 溶液滴定至终点,消耗30.00mL。则试样中As 2 O 3 和As 2 O 5...
【简答题】称取含 Na 2 S 试样 0.5000g ,溶于水后,加入 NaOH 溶液至碱性,加入过量的浓度为 0.02000mol/L 的 KMnO 4 标准溶液 25.00ml 将 S 2− 氧化为 SO 4 2− 。此时 KMnO 4 被还原为 MnO 2 ,过滤除去,将滤液酸化,加入过量的 KI ,再用 0.1000 mol/L Na 2 S 2 O 3 溶液滴定析出的 I 2 ,消耗 Na 2 S...
【简答题】To Make Everybody Happy Peter’s uncle lives in the country. Once in summer, Peter goes to stay with him for a few weeks. Whenever they go for a walk or for a drive in the car and pass somebody, his un...
【单选题】称取含有As 2 O 3 和As 2 O 5 的试样0.5000g,溶解后,在()溶液中用c(1/2I 2 )=0.1000mol/LI 2 溶液滴定至终点,消耗30.00mL。将此溶液调制(),加入过量KI,析出的I2用c(Na 2 S 2 O 3 )=0.3000mol/L的Na 2 S 2 O 3 溶液滴定至终点。