a)
$2Na + 2H_2O \to 2NaOH + H_2$
$2Al + 2NaOH + 2H_2O \to 2NaAlO_2 + 3H_2$
b)
$Ca + 2H_2O \to Ca(OH)_2 + H_2$
$2Al + Ca(OH)_2 + 2H_2O \to Ca(AlO_2)_2 + 3H_2$
\(a.Na+H_2O\rightarrow NaOH+\dfrac{1}{2}H_2\\ Al+H_2O+NaOH\rightarrow NaAlO_2+\dfrac{3}{2}H_2\)
\(b.Ca+2H_2O\rightarrow Ca\left(OH\right)_2+H_2\\ 2Al+2H_2O+Ca\left(OH\right)_2\rightarrow Ca\left(AlO_2\right)_2+3H_2\)
`a) `2Na +2(H_2)0 -> 2NaOH + H_2`
`2Al+2NaOH+2(H_2)0 -> 2NaAl0_2 + 3H_2`
`b) Ca+2(H_2)0 -> Ca(OH)_2 + H_2`
`Al+Ca(OH)_2+(H_2)0 -> Ca(AlO_2)_2 +H_2`
