The exact melting point of pure ethanoic acid is 290 Kelvin.
Understanding Ethanoic Acid and Its Physical Properties
Ethanoic acid, more commonly known as acetic acid, is a fundamental organic compound with the chemical formula CH₃COOH. It is recognized by its distinctive pungent, vinegar-like odor and appears as a clear, colorless liquid. A notable characteristic of pure ethanoic acid is its tendency to solidify into ice-like crystals at temperatures just below typical room temperature, earning it the alternative name 'glacial acetic acid'. This freezing behavior is directly linked to its specific melting point.
The melting point serves as a crucial physical property in chemistry, not only for identifying a substance but also for assessing its purity. For pure ethanoic acid, this precise temperature marks the transition point where it changes from its solid, frozen state back into a liquid.
The Significance of Ethanoic Acid's Melting Point
The melting point of pure ethanoic acid at 290 K (which is equivalent to approximately 16.85 °C or 62.33 °F) holds significant practical implications. This temperature is relatively close to the freezing point of water and can easily be encountered in many natural environments. As a result, pure ethanoic acid frequently freezes, forming solid, crystalline structures during winters in cold climates. This is a key reason for its "glacial" designation.
Awareness of this property is vital for anyone involved in the storage, handling, or industrial application of ethanoic acid, particularly in regions that experience colder temperatures. To ensure the acid remains in its usable liquid state, storage often requires temperature-controlled conditions.
Key Properties of Ethanoic Acid
Here are some essential physical properties of pure ethanoic acid for a comprehensive overview:
| Property | Value |
|---|---|
| Chemical Formula | CH₃COOH |
| Molar Mass | 60.05 g/mol |
| Appearance | Clear, colorless liquid |
| Odor | Pungent, vinegar-like |
| Melting Point | 290 K (16.85 °C) |
| Boiling Point | 391 K (118 °C) |
| Density (at 20 °C) | 1.049 g/cm³ |
Note: These values are typical and may vary slightly depending on specific measurement conditions.
Applications and Industrial Considerations
Ethanoic acid is a versatile chemical used across a wide spectrum of industries. Its applications range from its role as a solvent and a key reagent in chemical synthesis to its widespread use in the food industry as the main component of vinegar.
- Chemical Synthesis: It is a precursor for producing various chemicals, including vinyl acetate monomer (used in polymers), acetic anhydride, and numerous esters.
- Food Industry: Utilized as an acidulant, flavor enhancer, and preservative, primarily in the form of vinegar (a dilute solution).
- Solvent: Valued for its ability to dissolve a wide array of organic compounds.
- Medical and Pharmaceutical Use: Incorporated into certain pharmaceutical preparations and sometimes used as a mild antiseptic.
When storing or transporting pure ethanoic acid, particularly in colder climates, it is crucial to consider its 290 K melting point. Preventing solidification is essential as freezing can affect the acid's purity, handling efficiency, and accuracy in dosage for specific applications. Many industrial facilities implement heating or insulation measures to ensure the acid maintains its liquid form.
For further exploration of ethanoic acid and its properties, credible sources such as Wikipedia's page on Acetic Acid or established chemical reference resources like those from the Royal Society of Chemistry offer detailed information.
