\(a,\\ \left(1\right)SO_3+H_2O\rightarrow H_2SO_4\\ \left(2\right)CuO+H_2SO_4\rightarrow CuSO_4+H_2O\\ \left(3\right)CuSO_4+BaCl_2\rightarrow BaSO_4\downarrow+CuCl_2\\ b,\\ \left(1\right)Zn+2HCl\rightarrow ZnCl_2+H_2\\\left(2\right) H_2+CuO\underrightarrow{^{to}}Cu+H_2O\\ \left(3\right)SO_2+H_2O⇌H_2SO_3\\ \left(4\right)H_2SO_3+BaO\rightarrow BaSO_3\downarrow+H_2O\)