$2Na + 2H_2O \to 2NaOH + H_2$
$2NaOH + SO_2 \to Na_2SO_3 + H_2O$
$Na_2SO_3 + H_2SO_4 \to Na_2SO_4 + SO_2 + H_2O$
$Na_2SO_4 + BaCl_2 \to 2NaCl + BaSO_4$
$2NaCl + 2H_2O \xrightarrow{dpdd,cmn} 2NaOH + H_2 + Cl_2$
$NaOH + HCl \to NaCl + H_2O$
$NaCl + AgNO_3 \to AgCl + NaNO_3$
\(\left(1\right)Na+2H_2O\rightarrow2NaOH+H_2\\ \left(2\right)2NaOH+SO_2\rightarrow Na_2SO_3+H_2O\\ \left(3\right)Na_2SO_3+H_2SO_4\rightarrow Na_2SO_4+H_2O+SO_2\uparrow\\ \left(4\right)Na_2SO_4+BaCl_2\rightarrow2NaCl+BaSO_4\downarrow\\ \left(5\right)2NaCl+2H_2O\rightarrow^{\left(đpdd,cmm\right)}2NaOH+Cl_2\uparrow+H_2\uparrow\\ \left(6\right)NaOH+HCl\rightarrow NaCl+H_2O\\ \left(7\right)NaCl+AgNO_3\rightarrow NaNO_3+AgCl\downarrow\)