2Na3[Cr(OH)6] + 4NaOH + 3PbO2 → 2Na2CrO4 + 3Na2[Pb(OH)4] + 2H2O
Sodium hexahydroxochromate(III) react with sodium hydroxide and lead(IV) oxide to produce sodium chromate, sodium tetrahydroxoplumbate(II) and water. Sodium hydroxide - concentrated solution.