Citric acid, having the molecular formula C6H8O7, is a powerful organic compound but a weak organic acid.
Citric acid comes in two different forms: monohydrate and water-free (anhydrous). Citric acid can be found in a variety of plants and fruits, including lemons and oranges, with the tomato having the highest concentration. It’s also known as tribasic acid.
Citric acid is a white crystalline substance with no odor and a sour taste. Its crystal structure is monoclinic.
Molecular Formula -C6H8O7
The extended formula is CH2COOH-C(OH)COOH-CH2COOH.
Its molar mass is 192.12 g mol-1.
IUPAC name = 2-hydroxypropane-1, 2, 3-tricarboxylic acid
Structure of Citric Acid:
Citric Acid’s Applications
- Citric acid is commonly found in soft drinks, juices, and other liquids. It imparts a tangy, citrus flavor to them. Citric acid is a common flavoring ingredient.
- It works as a food preservative because its acidic pH prevents the growth of many bacteria in food, preventing spoilage. Citric acid lowers the pH of frozen foods, rendering oxidative enzymes inactive.
- Citric acid is also used to soften the basic pH of soaps and detergents.
- It’s also utilized as a preservative in many cosmetics to keep the acid-base pH balance. It’s used in cosmetics to exfoliate dead skin, as well as to reduce wrinkles and even out skin tone.
- Citric acid is used as an acidulant to manage pH levels and works as an anticoagulant by chelating calcium in the blood.
- Lemon peels, a source of citric acid, are utilized to boost bone health in conditions like osteoporosis because they contain a high level of calcium and vitamin C, which aid in bone maintenance.
- In the pharmaceutical sector, citric acid is utilized as a preservative for keeping blood.
- Some ice businesses employ citric acid as an emulsifier to avoid using fat globules as an emulsifying agent.
- In caramel, citric acid is used to prevent sugar crystallization.
- Citric acid is a crystalline white substance with no odor.
- It has a density of 1.542 g ml-1 (monohydrate form) and 1.665 g ml-1 (anhydrous form), with melting and boiling temperatures of 156 °C. and 310 °C respectively.
- Water, ether, acetone, ethanol, and methanol are extremely soluble, while toluene, benzene, and dichloromethane are insoluble.
- Citric acid is a weak acid, it is always in equilibrium in aqueous solution between the anionic -1, -2, and -3 forms and the neutral form.
- The more negative the charge on the anion, the more acidic it will be, with the pH of the associated aqueous solution ranging from pH 2 (for the CH2COOH-C(OH)COOH-CH2COO–) to pH 8 (for the CH2 COO-C(OH)COO-CH2COO-³).
- Citric acid is employed as a pH buffer regulator in many industrial processes because of this. Another essential feature of citric acid is its ability to bind metals, generating chelate metals that are comparable to EDTA complexes.