Question

If 34.3 mL of barium hydroxide are required to neutralize 15.9 mL of the acid, what is the molarity of the hydrochloric acid solution?

Answer 1

Ba(OH)2 + 2HCl ==> BaCl2 + 2H2O

You don't have enough info to answer. To know the M of the HCl you need the M of the Ba(OH)2.