一、课题的由来在一次学生实验中 ,几位同学偶然地错把Na2 S2 O3当成KSCN加入FeCl3中。正当他们准备将废液倒掉时 ,却惊奇地发现原来啤酒色的FeCl3溶液中泛起黑色的混浊 ,几秒钟后黑色变淡 ,不到 10s后黑色完全退去 ,在没有加入任何试剂的情况下溶液变得无色 ,澄清。他们向我询 First, the origin of the subject In a student experiment, several students mistakenly mistakenly added Na2S2O3 as KSCN to FeCl3. Just as they were preparing to drain the waste, they were surprised to find that the original beer-colored FeCl3 solution had a black turbidity and that after a few seconds the black became lighter and after less than 10 seconds the black completely receded without adding any reagents. The solution became colorless and clear. They asked me