$(a)$ Classify the following oxides as neutral,acidic,basic,or amphoteric:
$CO, B_2O_3, SiO_2, CO_2, Al_2O_3, PbO_2, Tl_2O_3$
$(b)$ Write suitable chemical equations to show their nature.

(N/A) $(1)$ $CO$: Neutral
$(2)$ $B_2O_3$: Acidic. It reacts with $NaOH$ to form sodium metaborate: $B_2O_3 + 2NaOH \longrightarrow 2NaBO_2 + H_2O$
$(3)$ $SiO_2$: Acidic. It reacts with $NaOH$ to form sodium silicate: $SiO_2 + 2NaOH \longrightarrow Na_2SiO_3 + H_2O$
$(4)$ $CO_2$: Acidic. It reacts with $NaOH$ to form sodium carbonate: $CO_2 + 2NaOH \longrightarrow Na_2CO_3 + H_2O$
$(5)$ $Al_2O_3$: Amphoteric. It reacts with both $NaOH$ and $H_2SO_4$: $Al_2O_3 + 2NaOH \longrightarrow 2NaAlO_2 + H_2O$ and $Al_2O_3 + 3H_2SO_4 \longrightarrow Al_2(SO_4)_3 + 3H_2O$
$(6)$ $PbO_2$: Amphoteric. It reacts with both $NaOH$ and $H_2SO_4$: $PbO_2 + 2NaOH \longrightarrow Na_2PbO_3 + H_2O$ and $2PbO_2 + 2H_2SO_4 \longrightarrow 2PbSO_4 + 2H_2O + O_2$
$(7)$ $Tl_2O_3$: Basic. It reacts with $HCl$ to form thallium chloride: $Tl_2O_3 + 6HCl \longrightarrow 2TlCl_3 + 3H_2O$