Sodium bicarbonate, or baking soda, is a versatile white powder used in homes for baking, cleaning, and deodorizing. A common question is whether sodium bicarbonate is corrosive. This article explores its properties to address this.
What Corrosive Means
A substance is considered corrosive if it causes irreversible damage to materials or living tissues through a chemical reaction. This damage involves breaking down or dissolving the substance it contacts. Corrosivity differs from abrasiveness, which is physical wear caused by friction. Strong acids and bases are common examples of corrosive chemicals, known for their ability to burn skin or dissolve metals.
How Sodium Bicarbonate Interacts with Materials
Sodium bicarbonate is generally not considered corrosive under normal conditions. Its mild alkaline (basic) nature, with a pH typically ranging from 8.3 to 8.5 in solution, makes it much less reactive than strong acids or bases. This gentle chemical profile allows for its widespread use.
When sodium bicarbonate interacts with metals, it is generally safe for most common types, such as stainless steel, copper, and brass. However, it can react slowly with very reactive metals like pure aluminum over prolonged exposure, forming a harmless oxide layer. Hot water solutions of baking soda can corrode steel.
For plastics and glass, sodium bicarbonate is non-damaging and safe to use. On organic materials and living tissues, like skin and eyes, it is mild compared to stronger chemicals and is often incorporated into home remedies.
Situations Requiring Care
While sodium bicarbonate is largely non-corrosive, certain situations warrant careful consideration. Highly concentrated solutions or thick pastes, especially with prolonged contact, might have a very mild chemical effect on extremely sensitive surfaces. The primary concern with such concentrated forms often relates to their physical, rather than chemical, properties.
Combining sodium bicarbonate with other chemicals can lead to corrosive reactions, but this effect stems from the mixture’s new chemical properties, not from the sodium bicarbonate itself. For instance, mixing it with strong acids produces a vigorous reaction, releasing carbon dioxide. Powdered sodium bicarbonate also exhibits a mild abrasive quality. This physical abrasiveness can cause wear on very soft or highly polished surfaces, such as painted finishes, mirrors, or delicate countertops, leading to micro-scratches. This abrasive action is distinct from chemical corrosion.
Safe Use and Storage
Sodium bicarbonate is widely recognized as safe for household use, but general precautions are advisable. If the powder or solution contacts eyes, flush immediately with water to alleviate mild irritation. When handling large quantities or in enclosed spaces, avoid inhaling the fine powder, as it can cause temporary respiratory irritation.
Proper storage helps maintain its effectiveness and prevents clumping. Sodium bicarbonate should be kept in a dry, sealed container, away from excessive heat, moisture, and strong acids. This ensures the substance remains stable and ready for its many common applications.