a, \(MgO+2HCl\rightarrow MgCl_2+H_2O\)
\(MgCO_3+2HCl\rightarrow MgCl_2+CO_2+H_2O\)
b, Ta có: \(n_{CO_2}=\dfrac{1,12}{22,4}=0,05\left(mol\right)\)
Theo PT: \(n_{MgCO_3}=n_{CO_2}=0,05\left(mol\right)\Rightarrow m_{MgCO_3}=0,05.84=4,2\left(g\right)\)
\(\Rightarrow m_{MgO}=5,2-4,2=1\left(g\right)\)