a,\(NaOH+HCl\rightarrow NaCl+H_2O\)
0,4__________0,4______0,4______
\(n_{NaOH}=\frac{16}{40}=0,4\left(mol\right)\)
\(m_{dd\left(HCl\right)}=\frac{0,4.36,5\%}{20\%}=73\left(g\right)\)
\(m_{NaCl}=0,4.58,5=23,4\left(g\right)\)
\(\Rightarrow C\%_{NaCl}=\frac{23,4}{16+73}.100\%=26,29\%\)