1/.
1) Na + H2O - > a + H2
2Na + 2H2O => 2NaOH + H2
2) b + H2O - > a
Na2O + H2O => 2NaOH
3) a + H2S04 -> c + H2O
2NaOH + H2SO4 => Na2SO4 + 2H2O
4) a + d - > Cu(OH)2 + NaCl
2NaOH + CuCl2 => Cu(OH)2 + 2NaCl
2/.
Ca(OH)2
avem 40 g Ca, 2x16 g O, 2x1 g H
=> Ca:O:H = 40:32:2
= 20:16:1