`(i) Pb_(3)O_(4)` is a stoichiometric mixtrue of two oxides i.e 2 mole of PbO and 1 mole of `PbO_(2)` In phO, the oxidation state of Pb is + 2 while it is +4 in `PbO_(2)`.Both these oxides can react with HCI .Therefore, the reaction may be split in to.