Wednesday, February 4, 2009

Physical Properties Of Ascorbic Acid







You can find ascorbic acid, also known as vitamin C, in oranges.








Ascorbic acid is also known as vitamin C. According to "Organic Chemistry, A Short Course," humans can't synthesize ascorbic acid from glucose -- it must be consumed in their diet. You can find ascorbic acid in citrus fruits such as oranges and in tomatoes. A diet deficient in ascorbic acid can lead to scurvy, which causes loosening of the teeth, an inability to heal wounds, hemorrhaging and eventually death. Ascorbic acid has several distinct physical properties.


Structure


Ascorbic acid has a chemical formula of C6H8O6. Four of the six carbons, along with one oxygen, are arranged in a five-sided ring. This ring contains a double bonded oxygen atom connected to one of the carbons. The ring of carbon and oxygen also has a double bond between two of the carbon atoms. Attached to each of these carbon atoms is a hydroxyl group. This arrangement is rather uncommon in organic compounds and is called an enediol. The molecular weight of ascorbic acid is 176.1 grams per mole.


Acidity


While ascorbic acid does not have an acid or carboxyl group, it does have an acidic hydrogen, a hydrogen that can be easily removed. Since ascorbic acid has an acidic hydrogen, it can behave like a weak acid when dissolved in water or when reacted with other compounds. Ascorbic acid has a pleasant acid taste.


Solubility


Ascorbic acid is water soluble; therefore, vitamin C is classified as a water soluble vitamin. Since vitamin C is water soluble, your body is unable to store reserves of this vitamin, so you must consume it regularly in your diet. Ascorbic acid is sparingly soluble in ethanol. It is insoluble in both ether and chloroform.


Other Physical Properties


Ascorbic acid is a colorless to almost white crystalline solid. It is odorless. Its melting point is 192 degrees Celsius, and it starts to decompose as it melts. Ascorbic acid mixed in sodium hydroxide, sodium carbonate or sodium bicarbonate has a pH of 5.5 to 7.0, while a 5 percent solution in water has a pH of 2.2 to 2.5.

Tags: Ascorbic acid, ascorbic acid, water soluble, acid also, acid also known