Ascorbic acid possesses following important physico-chemical properties:
a) It is a white crystalline substance.
b) It is freely soluble in water.
c) Solution of the vitamin tastes sour.
d) In dry condition it is stable in air and light.
e) It is fairly stable in cold acid solution.
f) In an aqueous medium, particularly alkaline, it is easily oxidized on exposure to heat, light and traces of metals such as copper or silver.
g) It is easily destroyed during cooking.
h) The compound is a powerful reducing agent and can reduce fehling's solution. This is due to the presence of en01 group (carbons 2 and 3) in its structure. (You have already learnt about the enol group in the carbohydrate Unit I).
i) Vitamin C also reduces 2, 6-dichlorophenolindophenol to a colourless leuco compound. This reaction is very commonly utilized for chemical estimation of the vitamin.