PT: \(FeCl_2+2NaOH\rightarrow2NaCl+Fe\left(OH\right)_{2\downarrow}\)
\(FeCl_3+3NaOH\rightarrow3NaCl+Fe\left(OH\right)_{3\downarrow}\)
\(CuSO_4+2NaOH\rightarrow Na_2SO_4+Cu\left(OH\right)_{2\downarrow}\)
\(SO_2+2NaOH\rightarrow Na_2SO_3+H_2O\)
\(SO_3+2NaOH\rightarrow Na_2SO_4+H_2O\)
\(H_2SO_4+2NaOH\rightarrow Na_2SO_4+2H_2O\)