Yes, citric acid can undergo decay, specifically a form of chemical breakdown known as decomposition, but this process is dependent on temperature.
Understanding Citric Acid Decomposition
Based on scientific information, citric acid is stable under normal conditions. However, when subjected to sufficient heat, it will break down.
According to the provided reference:
- It decomposes with loss of carbon dioxide above about 175 °C.
This means that the "decay" or decomposition of citric acid is a thermal process. When the temperature exceeds approximately 175 °C, the molecule begins to break down, releasing carbon dioxide gas.
Decomposition Conditions
The primary factor causing citric acid to decompose is heat.
| Condition | Effect on Citric Acid | Chemical Process |
|---|---|---|
| Above about 175 °C | Decomposes | Loses carbon dioxide |
This is distinct from biological decay, which involves microorganisms breaking down substances, commonly seen in food spoilage. Citric acid decomposition is a chemical reaction driven by heat.
Other Properties of Citric Acid
While decomposition occurs at high temperatures, under typical conditions, citric acid exhibits its acidic properties. It is known as a tribasic acid, meaning it has three acidic protons it can donate. The reference provides its acidity constant (pKa) values at a standard temperature:
- Citric acid is a tribasic acid, with pKa values, extrapolated to zero ionic strength, of 3.128, 4.761, and 6.396 at 25 °C.
These pKa values describe how readily citric acid loses its protons in solution at 25 °C, indicating its strength as an acid at that temperature. This is a different property from its decomposition temperature.
In summary, citric acid does not decay in the sense of biological spoilage under normal storage. However, it undergoes chemical decomposition when heated above approximately 175 °C, losing carbon dioxide in the process.
