\(n_{CO_2}=\dfrac{6,72}{22,4}=0,3mol\)
\(K_2CO_3+2HCl\rightarrow2KCl+H_2O+CO_2\)
\(BaCO_3+2HCl\rightarrow BaCl_2+H_2O+CO_2\)
\(MgCO_3+2HCl\rightarrow MgCl_2+H_2O+CO_2\)
\(\Rightarrow n_{CO_2}=n_{H_2O}=0,3mol\)
\(\Rightarrow\left\{{}\begin{matrix}m_{CO_2}=0,3\cdot44=13,2g\\m_{H_2O}=0,3\cdot18=5,4g\end{matrix}\right.\)
\(m_{HCl}=0,3\cdot2\cdot36,5=21,9g\)
BTKL: \(m_{hh}+m_{HCl}=m_{muối}+m_{CO_2}+m_{H_2O}\)
\(\Rightarrow41,9+21,9=m_{muối}+13,2+5,4\)
\(\Rightarrow m_{muối}=45,2g\)