A solution of HCl with a volume of 25.00 mL is titrated to the endpoint, with 0.250 M NaOH. If it takes 34.56 mL of NaOH, what is the original concentration of HCl in the
solution?
HCl(aq) + NaOH(aq) → H20(l)+ NaCl(aq)

Explanation:

= Volume of NaOH = 34.56 mL

= Volume of HCl = 25 mL

= Concentration of NaOH = 0.25 M

= Concentration of HCl

When endpoint is reached the number of moles of NaOH will be equal to the number of moles of HCl

Concentration of HCl is .

i'm assuming that the correct answer is indeed the first one/ "a"..