A 25.0 mL solution of HNO₃ is neutralized with 15.7 mL of 0.250 M Ba(OH)₂. What is the concentration of the original HNO₃ solution?

Answer 1

Ba(OH)₂ + 2HNO₃---> Ba(NO₃) + 2H₂O. We need to moles of nitric acid to neutralize the barium hydroxide. Multiplying the volume of the barium hydroxide (15.7mL) by the concentration yields 0.0039 moles. We need twice this amount, or 0.0079 moles of HNO₃. So, 0.0079 moles/0.025L=0.314 M HNO₃.