permanganate index use known excess KMnO4 with the sample of water first,
then the remaining KMnO4 is back titrated with excess standard C2O42-
the remaining C2O42- is finally titrated with standard KMnO4.
why not use standard C2O42- is back titrated remaining KMnO4, directly know the amount of remaining KMnO4 but use excess C2O42-?
C2O42- can be primary standard.
permanganate index 用2次excess?
2012-02-01 9:01 pm
回答 (2)
2012-02-03 12:00 am
✔ 最佳答案
因為如果由C2O4^2-滴定KMnO4 個終點變色唔明顯 因為本身MnO4^-係紫色 係一路滴定果陣 會慢慢變淺 淺到好似無色 好難分到幾時到終點所以唔準
但係由KMnO4 滴定C2O4^2- 終點係變紫色 所以準確得多
參考: my
2012-02-03 3:08 am
"then the remaining KMnO4 is back titrated with excess standard C2O42- "
KMnO4 just reacts with excess oxalate; there's no (back-)titration.
KMnO4 just reacts with excess oxalate; there's no (back-)titration.
收錄日期: 2021-04-16 13:57:39
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