posted by Janessa .
By titration it is found that 69.9 mL of 0.151 M NaOH(aq) is needed to neutralize 25.0 mL of HCl(aq). Calculate the concentration of the HCl solution.
mL1 x M1 = mL2 x M2
This equation works because the mols HCl = mols NaOH.