\(\begin{array}{l}
n_{ZnCl_2}=0,1.1,5=0,15(mol)\\
n_{Zn(OH)_2}=\frac{9,9}{99}=0,1(mol)\\
TH_1:\,KT\,ko\,tan\\
ZnCl_2+2NaOH\to Zn(OH)_2↓+2NaCl\\
Theo\,PT:\,n_{NaOH}=2n_{Zn(OH)_2}=0,2(mol)\\
\to a=\frac{0,2}{0,2}=1M\\
TH_2:\,KT\,tan\\
ZnCl_2+2NaOH\to Zn(OH)_2+2NaCl(1)\\
Zn(OH)_2+2NaOH\to Na_2ZnO_2+2H_2O(2)\\
Theo\,PT:\,n_{Zn(OH)_2(2)}=0,15-0,1=0,05(mol)\\
Theo\,PT:\,\sum n_{NaOH}=0,15.2+0,05.2=0,4(mol)\\
\to a=\frac{0,4}{0,2}=2M
\end{array}\)