In the permanganate titration of oxalic acid in the presence of bench H2SO4 (acid medium), it is found that there is slow discharge of the colour of permanganate solution in the beginning but after sometime, the discharge of the colour becomes faster. This is due to the formation of MnSO4 during the reaction which acts as a catalyst for the same reaction. Thus, Mn+2 is an "auto catalyst" for this reaction. This is an example of auto catalyst.