AL CHEM

紫心兒

titrate 25 cm^3 portion of the diluted mixture (oxalic acid and oxalate) against the given standardized 0.2M KMnO[size=-2]4. for each titration, you should add 20 cm^3 bencd dilute H[size=-2]2SO[size=-2]4 and heat the mixture to above 70度 before adding the permanganate. Further heating is necessary during the titration as the mixture is cooled down.

我想問點解個temperature below 70度會點?

同埋點解唔可以determine the conc. of permanganate by weighing and dissolving in a known volume of water


thx~

Andy Chen

1) The reation would be very slow?
2) KMnO4 cannot be obtained in highly pure from.
It is unstable and would decompose ( it is not good primary standard)
Equation: 4MnO4- + 2H2O -> 4MnO2 + 3O2 + 4OH-

Raul

我上個禮拜做