The ache, or \"burn\", you feel in your muscles during strenuous exercise is cau
ID: 491845 • Letter: T
Question
The ache, or "burn", you feel in your muscles during strenuous exercise is caused by the accumulation of lactic acid, which has the structure shown below. The hydrogen atom in the COOH group is acidic, and it can be removed using base to form a COO^- group. To determine the concentration of a solution of lactic acid, a chemist titrates a 21.50 mL sample of it with 0.1010 M NaOH, and finds that 14.83 mL of are required to reach the equivalence point. What is the concentration of the lactic acid solution in moles per liter?Explanation / Answer
For the acid base titrations
the mmoles of acid = mmoles of base
Thus
mmoles of acid used = 21.50 mL x M
mmoles of base = 14.83 mL x 0.1010 M
Thus molarity of acid = 14.83 mL x 0.1010 M / 21.50mL
= 0.6967 M
= 0.6967 mol/L