What fraction of the lactic acid/lactate mixture is lactic acid?

During exercise,  the pyruvate produced by the breakdown of glucose is converted into lactate. As some of the lactate hydrolyzes to lactic acid, high lactate levels can lead to acidity in the muscle cells. To calculate the fraction of that lactic acid in the mixture of lactate, we will divide the PH (say 3.24) of lactate with the PK-a (say 3.86) of the lactic acid. This will give us the fraction of lactic acid from lactate/lactic acid mixture.