Question

NA->Na2O->NaOH->NaCl->Na->NaOH->Na2CO3->CaCO3->CaO

Answer 1

4Na+O2=2Na2O

Na2O+H2O=2NaOH

NaOH+HCl=NaCl+H2O

2NaCl = 2Na + Cl2

2Na + 2H2O = 2NaOH + H2

2NaOH+H2CO3=Na2Co3+2H2O

Na2Co3+CaCl2=2NaCl+CaCo3

CaCO3=CaO+CO2

Answer 2

2Na + O2 → 2Na2O

Na2O + H2O → 2NaOH

NaOH + HCl → NaCl + H2O

Na в цепочке лишний

2NaCl + 2H2O → 2NaOH + Cl2↑ + H2↑

2NaOH + H2CO3 → Na2CO3 + 2H2O

Na2CO3 + Ca(OH)2 → 2NaOH + CaCO3

CaCO3 → CaO + CO2↑ (условие нагревания)