PT: \(MgO+2HCl\rightarrow MgCl_2+H_2O\)
\(Al_2O_3+6HCl\rightarrow2AlCl_3+3H_2O\)
Gọi: nH2O = x (mol)
Theo PT: \(n_{HCl}=2n_{H_2O}=2x\left(mol\right)\)
Theo ĐLBT KL, có: m oxit + mHCl = mmuối + mH2O
\(\Rightarrow12,2+2x.36,5=31,45+18x\)
⇒ x = 0,35 (mol)
⇒ nHCl (pư) = 0,35.2 = 0,7 (mol)
Ta có: \(n_{NaOH}=0,02.2=0,04\left(mol\right)\)
PT: \(NaOH+HCl_{\left(dư\right)}\rightarrow NaCl+H_2O\)
____0,04____0,04 (mol)
⇒ nHCl = 0,7 + 0,04 = 0,74 (mol)
\(\Rightarrow m_{ddHCl}=\dfrac{0,74.36,5}{20\%}=135,05\left(g\right)\)