The amount of lactic acid, HC3H5O3, produced in a sample of muscle tissue was analyzed by reaction with hydroxide ion. Hydroxide ion was produced in the sample mixture by electrolysis. The cathode reaction was
2H2O(l) + 2e → H2(g) + 2OH(aq)
Hydroxide ion reacts with lactic acid as soon as it is produced. The endpoint of the reaction is detected with an acid – base indicator. It required 115 s for a current of 15.6 mA to reach the endpoint. How many grams of lactic acid (a monoprotic acid) were present in the sample?