\(V_{HCl}=200ml=0,2l\\ n_{Mg}=\dfrac{6}{24}=0,25\left(mol\right)\\ PTHH:Mg+2HCl\xrightarrow[]{}MgCl_2+H_2\\ n_{HCl}=0,25.2=0,5\left(mol\right)\\ C_{MHCl}=\dfrac{0,5}{0,2}=2,5\left(M\right)\)
\(n_{Mg}=\dfrac{6}{24}=0,25\left(mol\right)\)
PT: \(Mg+2HCl\rightarrow MgCl_2+H_2\)
Theo PT: \(n_{MgCl_2}=n_{Mg}=0,25\left(mol\right)\)
\(\Rightarrow C_{M_{MgCl_2}}=\dfrac{0,25}{0,2}=1,25\left(M\right)\)