Definition

1. Noun:
   • A glassy solid acid: "metaphosphoric acid" refers to a specific inorganic chemical compound with the general formula (HPO₃)ₙ, where 'n' indicates it is a polymeric form. It is characterized by its glassy, vitreous solid state at room temperature.
   • A dehydrating agent: A primary function of metaphosphoric acid is its use as a dehydrating agent in chemical reactions and processes, meaning it has a strong affinity for removing water.

Usage Examples

• Noun:
  • The laboratory used metaphosphoric acid to prepare the anhydrous sample. (The laboratory used metaphosphoric acid to prepare the water-free sample.)
  • Metaphosphoric acid is a common reagent for stabilizing certain biological compounds. (Metaphosphoric acid is a common reagent for stabilizing certain biological compounds.)

Advanced Usage

• In analytical chemistry: Metaphosphoric acid is often employed as a protein precipitant and stabilizing agent in the analysis of substances like ascorbic acid (Vitamin C) to prevent oxidation.
  • The solution was treated with metaphosphoric acid prior to titration. (The solution was treated with metaphosphoric acid prior to titration.)

Variants and Related Words

• Phosphoric acid (H₃PO₄): A related, more common oxyacid of phosphorus from which metaphosphoric acid can be derived through dehydration.
• Polyphosphoric acid: A broader category of polymeric phosphoric acids that includes metaphosphoric acid forms.

Synonyms

• Glacial phosphoric acid: A historical synonym referencing its glassy, ice-like solid appearance.

Notes on Meaning

This term is highly specific to chemistry. It does not have different everyday meanings, idiomatic uses, or phrasal verbs. Its usage is confined to scientific and technical contexts describing the compound itself or its function as a reagent.

Noun

1. a glassy solid acid ([HPO3]n) often used as a dehydrating agent