\(A+HCl:\\ CuO+2HCl\rightarrow CuCl_2+H_2O\\ CaO+2HCl\rightarrow CaCl_2+H_2O\\ Fe_2O_3+6HCl\rightarrow2FeCl_3+3H_2O\\ B+Na_{dư}:\\ Na+H_2O\rightarrow NaOH+\dfrac{1}{2}H_2\\ CuCl_2+2NaOH\rightarrow Cu\left(OH\right)_2+2NaCl\\ FeCl_3+3NaOH\rightarrow Fe\left(OH\right)_3+3NaCl\\ \Rightarrow C:H_2; D:NaOH,NaCl,CaCl_2; E:Fe\left(OH\right)_3,Cu\left(OH\right)_2\)
\(CuO+2HCl\rightarrow CuCl_2+H_2O\\ CaO+2HCl\rightarrow CaCl_2+H_2O\\ Fe_2O_3+6HCl\rightarrow2FeCl_3+3H_2O\\ Na+H_2O\rightarrow NaOH+\dfrac{1}{2}H_2\\ 2NaOH+CuCl_2\rightarrow Cu\left(OH\right)_2\downarrow+2NaCl\\ FeCl_3+3NaOH\rightarrow Fe\left(OH\right)_3\downarrow+3NaCl\)
