Sunday, March 2, 2025

கொஞ்சம் கெமிஸ்ட்ரி ! - EP.006

 

Chemical Properties

  • Formula: H₃PO₄

  • Molar Mass: 97.99 g/mol

  • Appearance: Colorless solid or syrupy liquid

  • Odor: Odorless

  • Density: 1.6845 g/cm³ (25°C, 85% solution), 1.834 g/cm³ (solid)

  • Melting Point: 42.35°C (108.23°F) for anhydrous, 29.32°C (84.78°F) for hemihydrate

  • Boiling Point: 212°C (414°F) (only water evaporates)

  • Solubility: Highly soluble in water, soluble in ethanol

  • Refractive Index: 1.3420 (8.8% w/w aqueous solution), 1.4320 (85% aqueous solution at 25°C)

  • Viscosity: 2.4–9.4 cP (85% aqueous solution), 147 cP (100%)

Structure

Phosphoric acid has a tetrahedral molecular shape with a central phosphorus atom bonded to four oxygen atoms. It forms three classes of salts corresponding to the replacement of one, two, or three hydrogen atoms.

Production

  • Wet Process: Produced by reacting phosphate rock with sulfuric acid.

  • Dry Process: Produced by burning elemental phosphorus to form phosphorus pentoxide, which is then hydrated.

Uses

  • Fertilizers: Used to make phosphate salts for fertilizers.

  • Food Industry: Serves as an acidic, fruit-like flavoring in food products.

  • Dental Cements: Used in the preparation of dental cements.

  • Industrial: Employed in the sugar and textile industries, and in the preparation of albumin derivatives.

Safety and Hazards

  • Hazard Statements: H290 (May be corrosive to metals), H314 (Causes severe skin burns and eye damage)

  • Precautionary Statements: P280 (Wear protective gloves/protective clothing/eye protection/face protection), P305+P351+P338 (IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continue rinsing), P310 (Immediately call a POISON CENTER or doctor/physician)

  • NFPA 704 (Fire Diamond): 3 (Health), 0 (Flammability), 0 (Reactivity)

  • Lethal Dose (LD50): 1530 mg/kg (rat, oral)

Environmental Impact

Phosphoric acid is not biodegradable but is generally considered safe for the environment when used appropriately.

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கொஞ்சம் கெமிஸ்ட்ரி ! - EP.019

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