How is oxalic acid vs NaOH titration different from oxalic acid vs potassium permegnate titration?
The former is a acid base neutralisation reaction whereas the latter is a redox reaction.
Potassium Permanganate (KMnO4) reacts with Sulphuric acid (H2SO4) to produce Manganese Heptoxide (MnO7), water (H20) and Potassium Hydrogen Sulphate (KHSO4)2. The reactive species produced is Manganese Heptoxide (which is a very powerful oxidiser). The Manganese Heptoxide will oxidise the Oxalic acid (COOH)2 to Carbon dioxide (CO2).
I believe it is necessary to rinse the conical flask with oxalic acid before use, unless you are sure that the conical flask is really clean and dry before use. However to prevent having any types of unwanted chemical reaction when you pour the oxalic acid in the flask, it is best to rinse it with oxalic acid before use, so that there will not be errors like e.g. there is no pinkish color formed…
What is the colour change in the titration of NaOH and C2H2O4 if using phenolphthalein as an indicator?
Rhubarb leaves contain oxalic acid. So too does the stem itself. Tomatoes also contain oxalic acid, especially the leaves. Oxalic acid is a poison. Oxalic acid is also found in potatoes and in peppers as well as in peas. Oxalic acid becomes concentrated in tomato paste. In the tomato, red tomato's have less oxalic acid than do green tomato's.