Used as a reducing agent in analytical chemistry, particularly as a primary standard for the standardization of potassium permanganate (KMnO₄) solutions in redox titrations. It reacts quantitatively with strong oxidizing agents like permanganate in acidic conditions, making it suitable for determining iron content or other reductants.

Also employed in medical testing to remove calcium from blood samples, acting as an anticoagulant by chelating calcium ions to prevent clotting.

In industrial processes, it serves as a chelating agent for metal ions, including in metal cleaning applications to remove oxides or scale from surfaces, particularly iron and manganese.

In biochemical research, sodium oxalate inhibits enzymes that require magnesium or calcium as cofactors by binding these ions, thereby reducing enzyme activity.

Additionally, it is used in the synthesis of other oxalate compounds and in cleaning formulations to dissolve calcium deposits.

Safety note: Sodium oxalate is toxic if ingested or absorbed; it can bind calcium in the blood, potentially causing hypocalcemia. Handle with care.