which acid to acidify KMnO4

Q:
Is KMnO4 acidified by dilute sulphuric acid??

A:
Yes, but just a few drops will do. Remember not to use dilute HCl instead.

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Q:
Why dont use the conc.sulphuric acid or conc.nitric acid to acidify it as they have a higher [h+]( Cl- reacts with MnO4-)

A:
As, conc. sulphuric acid and conc. nitric acid are OA, they cannot be added to KMnO4 as they will disturb the reaction. In a chemical reaction, we must ensure that KMnO4 is the ONLY oxidizing agent that reacts in a redox reaction.

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Q:
my friend said that HNO3 and conc.sulphuric acid reacted with MnO4- ( redox) but i remember that HNO3 and conc.sulphuric acid and MnO4- are OA.
Why there are redox reaction between them? Or my friend is wrong?

A:
First and foremost, it is important to note that either conc. or dil. nitric acid can react with KMnO4 to undergo redox reaction. This is simply because conc. and dil. nitric acid are both strong OA. Although MnO4- has a higher electrode potential than NO3-, there are still some chances that NO3- would also react in the redox reaction. So, your friend is partly correct.

Both conc. and dil. sulphuric acid are OA, but their oxidizing power are incredibly lower than that of nitric acid. So, you can use both conc. and dil. sulphuric acid to acidify KMnO4. However, it is very unusual to use conc. sulphuric acid to acidify KMnO4 in laboratory experiments. (If you really have to use it, add only a trace amount will do.)

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Lastly, the main reason that we don't usually use either nitric acid or conc. sulphuric acid to acidify KMnO4 is we must try our very best to take out every single factor that may cause inaccuracy in experimental results. In order to safeguard the accuracy and reliability of experimental results, we should use only dil. sulphuric acid to acidify KMnO4.

Hope I can solve your question! ;)