\(a,\left\{{}\begin{matrix}m_{H_2SO_4}=\dfrac{300\cdot9,8\%}{100\%}=29,4\left(g\right)\\m_{BaCl_2}=\dfrac{200\cdot26\%}{100\%}=52\left(g\right)\end{matrix}\right.\\ \Rightarrow\left\{{}\begin{matrix}n_{H_2SO_4}=\dfrac{29,4}{98}=0,3\left(mol\right)\\n_{BaCl_2}=\dfrac{52}{208}=0,25\left(mol\right)\end{matrix}\right.\\ PTHH:H_2SO_4+BaCl_2\rightarrow2HCl+BaSO_4\downarrow\)
Vì \(\dfrac{n_{H_2SO_4}}{1}>\dfrac{n_{BaCl_2}}{1}\) nên sau phản ứng \(H_2SO_4\) dư
\(\Rightarrow n_{BaSO_4}=0,25\left(mol\right)\\ \Rightarrow a=m_{BaSO_4}=0,25\cdot233=58,25\left(g\right)\)
\(b,n_{HCl}=2n_{BaCl_2}=0,5\left(mol\right)\\ \Rightarrow m_{CT_{HCl}}=0,5\cdot36,5=18,25\left(g\right)\\ m_{dd_{HCl}}=300+200-58,25=441,75\left(g\right)\\ \Rightarrow C\%_{HCl}=\dfrac{18,25}{441,75}\cdot100\%\approx4,13\%\)