Ionic Equilibrium

2.5 mL of \(\frac{2}{5}\)M weak monoacidic base (K\(_b\) = 1 \(\times\) 10\(^{-12}\) at 25\(^\circ\)C) is titrated with \(\frac{2}{15}\)M HCl in water at 25\(^\circ\)C. The concentration of H\(^+\) at equivalence point is (K\(_w\) = 1 \(\times\) 10\(^{-14}\) at 25\(^\circ\)C).