a) \(2K+2H_2O\rightarrow2KOH+H_2\)
b)
\(Ca+2H_2O\rightarrow Ca\left(OH\right)_2+H_2\)
\(Ca\left(OH\right)_2+Na_2CO_3\rightarrow CaCO_3+2NaOH\)
c)
\(Ba+2H_2O\rightarrow Ba\left(OH\right)_2+H_2\)
\(Ba\left(OH\right)_2+2NaHSO_4\rightarrow BaSO_4+Na_2SO_4+2H_2O\)
d)
\(2Na+2H_2O\rightarrow2NaOH+H_2\)
\(3NaOH+AlCl_3\rightarrow Al\left(OH\right)_3\downarrow+3NaCl\)
\(Al\left(OH\right)_3+NaOH\rightarrow NaAlO_2+2H_2O\)
e)
\(Ba+2H_2O\rightarrow Ba\left(OH\right)_2+H_2\)
\(Ba\left(OH\right)_2+2NH_4NO_3\rightarrow Ba\left(NO_3\right)_2+2NH_3+2H_2O\)
f) \(2Na+2H_2O\rightarrow2NaOH+H_2\)
\(2Al+2NaOH+2H_2O\rightarrow2NaAlO_2+3H_2\)