a,
$n_{H_2SO_4\text{bđ}}=\dfrac{125.19,6\%}{98}=0,25 mol$
$n_{NaOH}=0,2 mol$
$2NaOH+H_2SO_4\to Na_2SO_4+2H_2O$
$\Rightarrow n_{H_2SO_4\text{dư}}=0,2:2=0,1 mol$
$\Rightarrow n_{H_2SO_4\text{pứ}}=0,25-0,1=0,15 mol$
$ZnO+H_2SO_4\to ZnSO_4+H_2O$
$\Rightarrow n_{ZnO}=n_{ZnSO_4}=0,15 mol$
$m=0,15.81=12,15g$
$m_{ZnSO_4}=161.0,15=24,15g$
b,
$ZnO+2KOH\to K_2ZnO_2+H_2O$
$\Rightarrow n_{KOH}=0,15.2=0,3 mol$
$\Rightarrow m_{\text{dd KOH}}=0,3.56:11,2\%=150g$