Procedures
1.Weigh out accurately about 1.575g ethane -1,2-dioic acid, dissolve in water and make up to 250cm3.
2. Pipeete 25cm3 of the prepared solution into a conical flask. Add about 25cm3 of 1M H2SO4 and heat the mixture on a tripod to 70 degreeC.
3. Titrate with the potassium permanganate solution till a permanet pink coloration is observed.
4. Repeat the titration for three times.
I would like to ask why we have to add H2SO4 to the ethane-1,2-dioic acid and heat it beofore titration start. What is the principle behind this action?
principle of redox titration
2010-10-26 7:15 am
回答 (2)
2010-10-26 9:22 pm
✔ 最佳答案
you're titrating permanganate against oxalic acid. this reaction involves vigorous oxidative environment, which requires acidified permanganate. acidity of oxalic acid isn't enough, so extra sulphuric acid is added. the reaction is extraordinarily slow initially. to avoid adding excess permanganate in titration before complete reaction, the mixture is heated to speed up the reaction.
the reaction mixture doesn't need to be kept hot. the manganese(II) ion produced in the reaction is a catalyst for same reaction. it's called auto-catalyis.
2010-10-27 8:35 pm
Well, it is a redox reaction, isn't it?
Permanganate is the oxidizing agent.
At CE level, we know that permanganate has to be acidified in order to carry out the oxidation of the other reactant - in this case, ethan-1,2-dioic acid.
This is why we act sulphuric acid I guess.
Also, heating may speed up reactions.
Permanganate is the oxidizing agent.
At CE level, we know that permanganate has to be acidified in order to carry out the oxidation of the other reactant - in this case, ethan-1,2-dioic acid.
This is why we act sulphuric acid I guess.
Also, heating may speed up reactions.
收錄日期: 2021-04-19 23:27:17
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