Sodium Sulfite Oxygen Scavenger Reaction

Chemical reaction by which sodium sulfite scavenges residual dissolved oxygen in feedwater, forming sodium sulfate. Used in low-pressure boilers below roughly 900 psi.

$$2\mathrm{N}{\mathrm{a}}_2\mathrm{S}{\mathrm{O}}_3+{\mathrm{O}}_2\to 2\mathrm{N}{\mathrm{a}}_2\mathrm{S}{\mathrm{O}}_4$$

Variables

Symbol	Meaning	Unit
Na2SO3	Sodium sulfite (oxygen scavenger)	mol
O2	Dissolved oxygen	mol
Na2SO4	Sodium sulfate (product, adds dissolved solids)	mol

Worked example

Two moles of sulfite react with one mole of oxygen.

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Part of The Blueprint of Water