$A$: $Na$
$B$: $Na_{2}O$
$C$: $NaOH$
$D$: $Na_{2}SO_{4}$
$E$: $NaCl$
$PTHH: 4Na+CO_{2} \xrightarrow {t^o} 2Na_{2}O+C$
$PTHH:Na_{2}O+H_{2}O→2NaOH$
$PTHH:2NaOH+H_{2}SO_{4}→Na_{2}SO_{4}+2H_{2}O$
$PTHH:Na_{2}SO_{4}+BaCl_{2}→BaSO_{4}↓+2NaCl$
$PTHH:2NaCl \xrightarrow {đpnc} 2Na +Cl_{2}$