\(n_{H^+}=0.1\cdot1+0.1\cdot2\cdot0.5=0.2\left(mol\right)\)
\(H^++OH^-\rightarrow H_2O\)
\(0.2........0.2\)
\(n_{NaOH}=0.2\left(mol\right)\)
\(m_{NaOH}=0.2\cdot40=8\left(g\right)\)
\(m_{dd_{NaOH}}=\dfrac{8\cdot100}{20}=40\left(g\right)\)
\(V_{dd_{NaOH}}=\dfrac{40}{1.25}=32\left(ml\right)\)