\(a,\left(1\right)4Na+O_2\underrightarrow{t^o}2Na_2O\\ \left(2\right)Na_2O+H_2O\rightarrow2NaOH\\ \left(3\right)Na+H_2O\rightarrow NaOH+\dfrac{1}{2}H_2\\ b,4P+5O_2\underrightarrow{t^o}2P_2O_5\\ \left(2\right)P_2O_5+3H_2O\rightarrow2H_3PO_4\\ \left(3\right)2H_3PO_4+3ZnO\rightarrow Zn_3\left(PO_4\right)_2+3H_2O\\ c,\left(1\right)Fe_2O_3+3CO\underrightarrow{t^o}2Fe+3CO_2\\ \left(2\right)Fe+CuSO_4\rightarrow FeSO_4+Cu\downarrow\)