ANS:C - HPO₃

Metaphosphoric acid, with the chemical formula 𝐻𝑃𝑂3HPO3​, is a type of phosphoric acid. It is also known as orthophosphoric acid or simply phosphoric acid. Here's an explanation of metaphosphoric acid:

1. Chemical Structure: Metaphosphoric acid is a simple polyphosphoric acid compound. It consists of a single phosphorus atom (P) bonded to three oxygen atoms (O) and one hydrogen atom (H). The molecular structure can be represented as 𝐻𝑃𝑂3HPO3​.
2. Acidic Properties: Like other phosphoric acids, metaphosphoric acid is acidic due to the presence of hydrogen ions (H+). In aqueous solutions, metaphosphoric acid dissociates into hydrogen ions and metaphosphate ions (𝐻𝑃𝑂3−HPO3−​). The dissociation process can be represented as follows: 𝐻𝑃𝑂3→𝐻++𝑃𝑂3−HPO3​→H++PO3−​ The hydrogen ions contribute to the acidic nature of metaphosphoric acid, making it capable of donating protons to other substances.
3. Uses: Metaphosphoric acid has various applications in analytical chemistry, particularly in the food industry. It is commonly used as a preservative and antioxidant in food and beverage products. Metaphosphoric acid helps prevent oxidation and spoilage by chelating metal ions and inhibiting enzymatic browning reactions in fruits and vegetables. It is also used in the extraction and analysis of organic compounds, particularly in protein precipitation and nucleic acid isolation techniques.
4. Forms: Metaphosphoric acid can exist in different forms, including the anhydrous form (𝐻𝑃𝑂3HPO3​), as well as hydrated forms such as orthophosphoric acid (𝐻3𝑃𝑂4H3​PO4​) and pyrophosphoric acid (𝐻4𝑃2𝑂7H4​P2​O7​). The specific form depends on factors such as concentration, temperature, and pH of the solution.

Overall, metaphosphoric acid is a valuable chemical compound with diverse applications in various industries, particularly in food preservation and analytical chemistry. Its ability to inhibit oxidation and preserve freshness makes it an important ingredient in the food and beverage industry, while its chemical properties make it useful in laboratory analyses and research.