Ta có: \(m_{BaCl_2}=200.5,2\%=10,4\left(g\right)\Rightarrow n_{BaCl_2}=\dfrac{10,4}{208}=0,05\left(mol\right)\)
\(m_{H_2SO_4}=58,8.20\%=11,76\left(g\right)\Rightarrow n_{H_2SO_4}=\dfrac{11,76}{98}=0,12\left(mol\right)\)
PT: \(BaCl_2+H_2SO_4\rightarrow BaSO_{4\downarrow}+2HCl\)
Xét tỉ lệ: \(\dfrac{0,05}{1}< \dfrac{0,12}{1}\), ta được H2SO4 dư.
Theo PT: \(\left\{{}\begin{matrix}n_{H_2SO_4\left(pư\right)}=n_{BaSO_4}=n_{BaCl_2}=0,05\left(mol\right)\\n_{HCl}=2n_{BaCl_2}=0,1\left(mol\right)\end{matrix}\right.\)
⇒ nH2SO4 (dư) = 0,12 - 0,05 = 0,07 (mol)
Ta có: m dd sau pư = m dd BaCl2 + m dd H2SO4 - mBaSO4 = 200 + 58,8 - 0,05.233 = 247,15 (g)
\(\Rightarrow\left\{{}\begin{matrix}C\%_{H_2SO_4\left(dư\right)}=\dfrac{0,07.98}{247,15}.100\%\approx2,78\%\\C\%_{HCl}=\dfrac{0,1.36,5}{247,15}.100\%\approx1,48\%\end{matrix}\right.\)
Bạn tham khảo nhé!