a)
$2Na + 2H_2O \to 2NaOH + H_2$
$Na_2O + H_2O \to 2NaOH$
$Na_2CO_3 + Ca(OH)_2 \to CaCO_3 + 2NaOH$
$BaO + H_2O \to Ba(OH)_2$
$Ba(OH)_2 + Na_2CO_3 \to BaCO_3 + 2NaOH$
b)
$CuO + 2HCl \to CuCl_2 + H_2O$
$CuCl_2 + 2NaOH \to Cu(OH)_2 + 2NaCl$
$CuCl_2 + Ca(OH)_2 \to Cu(OH)_2 + CaCl_2$
$CuSO_4 + 2NaOH \to Cu(OH)_2 + Na_2SO_4$
$CuSO_4 + Ca(OH)_2 \to CaSO_4 + Cu(OH)_2$
$Cu(NO_3)_2 + 2NaOH \to Cu(OH)_2 + 2NaNO_3$
$Cu(NO_3)_2 + Ca(OH)_2 \to Ca(NO_3)_2 + Cu(OH)_2$
a)
2Na+2H2O→2NaOH+H22Na+2H2O→2NaOH+H2
Na2O+H2O→2NaOHNa2O+H2O→2NaOH
Na2CO3+Ca(OH)2→CaCO3+2NaOHNa2CO3+Ca(OH)2→CaCO3+2NaOH
BaO+H2O→Ba(OH)2BaO+H2O→Ba(OH)2
Ba(OH)2+Na2CO3→BaCO3+2NaOHBa(OH)2+Na2CO3→BaCO3+2NaOH
b)
CuO+2HCl→CuCl2+H2OCuO+2HCl→CuCl2+H2O
CuCl2+2NaOH→Cu(OH)2+2NaClCuCl2+2NaOH→Cu(OH)2+2NaCl
CuCl2+Ca(OH)2→Cu(OH)2+CaCl2CuCl2+Ca(OH)2→Cu(OH)2+CaCl2
CuSO4+2NaOH→Cu(OH)2+Na2SO4CuSO4+2NaOH→Cu(OH)2+Na2SO4
CuSO4+Ca(OH)2→CaSO4+Cu(OH)2CuSO4+Ca(OH)2→CaSO4+Cu(OH)2
Cu(NO3)2+2NaOH→Cu(OH)2+2NaNO3Cu(NO3)2+2NaOH→Cu(OH)2+2NaNO3
Cu(NO3)2+Ca(OH)2→Ca(NO3)2+Cu(OH)2