Question

A 0.025L sample of HCl(aq) is titrated with 0.0672L of 0.125mol/L of KOH(aq). What is the concentration of the acid?

Answer 1

I calculated there are 0.0084mols of OH-. (0.125mol/L) x (0.0672L)

Answer 2

so you know you need that many moles to achieve neutrality.
now use the volume of the acid you had and knowing that it had that many moles of acid, calculate the molarity.

M=n/L of solution