Gọi \(\left\{{}\begin{matrix}n_{Ca}:x\left(mol\right)\\n_{CaCO3}:y\left(mol\right)\end{matrix}\right.\)
\(Ca+2HCl\rightarrow CaCl_2+H_2\)
x_____2x_____x_________x
\(CaCO_3+2HCl\rightarrow CaCl_2+CO_2+H_2O\)
y________2y________y________y_________
\(\Rightarrow\left\{{}\begin{matrix}40x+100y=24\\x+y=\frac{6,72}{22,4}=0,3\left(mol\right)\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=0,1\left(mol\right)\\y=0,2\left(mol\right)\end{matrix}\right.\)
\(\Rightarrow\left\{{}\begin{matrix}\%m_{Ca}=\frac{0,1.40}{24}.100\%=16,67\%\\\%m_{CaCO3}=100\%-16,67\%=83,33\%\end{matrix}\right.\)
\(n_{HCl\left(bđ\right)}=\left(0,1.2+0,2.2\right).110\%=0,66\left(mol\right)\)
\(V_{dd\left(HCl\right)}=\frac{0,66}{2}=0,33\left(l\right)\)
\(\Rightarrow CM_{CaCl2}=\frac{0,1+0,2}{0,33}=0,9M\)