$a.PTHH : \\Zn+2HCl\to ZnCl_2+H_2↑(1) \\ZnO+2HCl\to ZnCl_2+H_2O(2) \\b.n_{H_2}=\dfrac{2,24}{22,4}=0,1mol \\Theo\ pt\ (1) : \\n_{Zn}=n_{H_2}=0,1mol \\⇒m_{Zn}=0,1.65=6,5g \\⇒m_{ZnO}=14,6-6,5=8,1g \\c.n_{ZnO}=\dfrac{8,1}{81}=0,1mol \\Theo\ pt\ (1) : \\n_{HCl(1)}=2.n_{Zn}=2.0,1=0,2mol \\Theo\ pt\ (2) : \\n_{HCl(2)}=2.n_{ZnO}=2.0,1=0,2mol \\⇒m_{HCl}=36,5.(0,2+0,2)=14,6g \\⇒m_{dd\ HCl}=\dfrac{14,6}{7,3\%}=200g$