Vitamin C (Ascorbic acid)
Vitamin C, ascorbic acid is also called anti-scorbutic vitamin. Ascorbic acid occurs as white crystals or white crystalline powder without odour and of citric acid like taste. Turns pale yellow on prolonged storage. Ascorbic acid is easily soluble in water, soluble in methanol, ethanol and glycerin and insoluble in ether, chloroform, benzene, petroleum ether, fats and fatty oils. The pH values of aqueous ascorbic acid solutions are:
1% (w/v) solution is about pH 2.8; 5% (w/v) solution is about pH 2.5; 10% (w/v) solution is about pH 2.4; 20% (w/v) solution is about pH 2.2
Ascorbic acid reacts like strong, monobasic acid. The action of atmospheric oxygen as well as exposure to daylight and UV light causes rapid destruction of ascorbic acid in aqueous solutions. Ascorbic acid is also destroyed by the action of oxidizing agents and heavy metal ions and in the presence of alkalies