1. Properties of Diluted Hydrofluoric Acid:

• Physical State: A colorless liquid with a sharp, pungent odor. Miscible with water in all proportions.
• Concentration: Commonly available in diluted concentrations, such as 10% to 50% by weight in water. The concentration determines its reactivity and safety measures.
• Reactivity: Reacts with many materials, including glass and metals, by dissolving oxides and silicates. Generates heat when diluted further.
• Toxicity: Highly toxic and corrosive, even at low concentrations. Capable of penetrating skin and tissues, leading to systemic toxicity.

2. Applications of Diluted Hydrofluoric Acid:

• Industrial Uses:
  • Etching and Cleaning: Used for etching glass, semiconductors, and metals.
  • Oil Refining: Acts as a catalyst in the alkylation process to produce high-octane fuel.
  • Pickling: Cleans stainless steel and other metals by removing oxide layers.
• Laboratory Uses:
  • Dissolves silicates for chemical analysis.
  • Used in geochemistry to prepare samples for study.
• Consumer Products (Rare and Controlled):
  • Found in diluted forms in some rust removers or specialty cleaning agents.
• Environmental Applications:
  • Used in wastewater treatment to adjust pH or dissolve silica.

3. Safety and Handling of Diluted Hydrofluoric Acid:

• Hazards:
  • Corrosive: Can cause severe burns and tissue damage.
  • Systemic Toxicity: Fluoride ions can disrupt calcium and magnesium in the body, leading to severe health issues, including cardiac arrest.
  • Inhalation Risk: Vapors can damage respiratory tissues.
• Protective Measures:
  • Always use in a well-ventilated area or fume hood.
  • Wear appropriate personal protective equipment (PPE), including acid-resistant gloves, goggles, and aprons.
  • Avoid skin and eye contact at all costs.
• First Aid:
  • Skin Contact: Rinse immediately with copious amounts of water and apply calcium gluconate gel to neutralize fluoride ions.
  • Eye Contact: Flush with water for at least 15 minutes and seek immediate medical attention.
  • Inhalation: Move to fresh air and seek emergency medical care.

4. Storage:

• Store in a tightly closed polyethylene or Teflon container, away from metals and incompatible substances.
• Keep in a cool, well-ventilated area.

5. Common Diluted Concentrations:

• 1-5%: Laboratory use, minimal etching.
• 10-20%: Moderate etching or cleaning applications.
• 40-50%: Industrial use, strong etching and cleaning applications.