${\text{Pb}}_3{\text{O}}_{\text{4}}+8\text{\hspace{0.17em}HCl}\underset{ }{\overset{ }{\to }}3{\text{\hspace{0.17em}PbCl}}_2+{\text{Cl}}_2+4{\text{\hspace{0.17em}H}}_{\text{2}}\text{O}$ .

One mole of ${\text{Pb}}_{\text{3}}{\text{O}}_{\text{4}}$ oxidizes ______ moles of HCl

Pb₃O₄ is PbO₂.2PbO

$\stackrel{+4}{\mathrm{Pb}}{O}_2+4H\stackrel{-}{Cl}\to \stackrel{+2}{Pb}C{l}_2+\stackrel{0}{C{l}_2}+2H_{2}O$

$2\stackrel{+2}{\mathrm{Pb}}\mathrm{O}+4\mathrm{H}\stackrel{-}{\mathrm{Cl}}\to 2{\mathrm{PbCl}}_2+2{\mathrm{H}}_2\mathrm{O}$

Only 2 moles of HCl oxidized to ${\text{Cl}}_2$