A là HCl, B là Ba(OH)2
(1) \(HCl+NaOH\rightarrow NaCl+H_2O\)
(2) \(H_2O+BaO\rightarrow Ba\left(OH\right)_2\)
(3) \(Ba\left(OH\right)_2+SO_2\rightarrow BaSO_3+H_2O\)
(4) \(2HCl+Fe\rightarrow FeCl_2+H_2\)
A: Fe(OH)2
B: Ba(OH)2
PTHH:
\(\left(1\right)Fe\left(OH\right)_2\underrightarrow{to}FeO+H_2O\\ \left(2\right)BaO+H_2O\rightarrow Ba\left(OH\right)_2\\ \left(3\right)Ba\left(OH\right)_2+Na_2SO_3\rightarrow BaSO_3+2NaOH\\ \left(4\right)Fe\left(OH\right)_2+2HCl\rightarrow FeCl_2+2H_2O\)