Sodium bicarbonate vs Sodium carbonate: what is the difference?

How they differ

Baking soda and washing soda are the same two elements in different proportions, NaHCO3 against Na2CO3, and the extra sodium makes all the difference to how alkaline they are. Sodium bicarbonate is mildly alkaline and safe to eat, which is why it leavens cake and settles indigestion. Sodium carbonate is strongly alkaline, will irritate skin, and is used to soften laundry water and cut grease. Heating baking soda in an oven converts it into washing soda, releasing carbon dioxide and water, which is the same reaction that raises a cake. In baking, the carbon dioxide is the point; in cleaning, the alkalinity is.

Side by side

Structural similarity 0.67 of 1, computed as a Morgan fingerprint Tanimoto coefficient. It measures shape, not effect.

Common questions

What is the difference between Sodium bicarbonate and Sodium carbonate?

Baking soda and washing soda are the same two elements in different proportions, NaHCO3 against Na2CO3, and the extra sodium makes all the difference to how alkaline they are. Sodium bicarbonate is mildly alkaline and safe to eat, which is why it leavens cake and settles indigestion. Sodium carbonate is strongly alkaline, will irritate skin, and is used to soften laundry water and cut grease.

Is Sodium bicarbonate bigger than Sodium carbonate?

Sodium carbonate is the heavier molecule, 105.99 g/mol against 84.01 g/mol for Sodium bicarbonate. Sodium bicarbonate is CHNaO3 and Sodium carbonate is CNa2O3.

Which has the lower reported LD50, Sodium bicarbonate or Sodium carbonate?

Sodium carbonate, at 2,800 mg/kg (oral, rat), against 4,220 mg/kg (oral, rat) for Sodium bicarbonate. An LD50 is one acute animal measurement, and the two here were not necessarily measured in the same species, so it is a data point rather than a ranking of how dangerous either is to a person.