[Chemistry Class Notes] on Phosphorus Pentachloride Pdf for Exam

Phosphorus pentachloride is a greenish-yellow crystalline solid, It is decomposed by water to form hydrochloric acid and phosphoric acid with the release of heat energy. It can also be prepared by the action of dry chlorine on phosphorus trichloride. The chemical formula for phosphorus pentachloride is PCl₅. In a solid state, it exists as PCl₄PCl₄⁺PCl₆PCl₆^–.

Phosphorus pentachloride vaporizes without dissociation in an atmosphere of phosphorus trichloride or chlorine gas. The dissociation equilibrium is shifted to the left side by the presence of the product.

Structure of Phosphorus Pentachloride

The hybridization in phosphorus pentachloride is sp³d and it has a trigonal bipyramidal geometry in gaseous and liquid states. It has two axial P−Cl bonds and three equatorial P−Cl bonds.

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Properties of Phosphorus Pentachloride

Uses of Phosphorus Pentachloride (PCl₅)

• It is used as a chlorinating agent.

• It is used for the manufacture of penicillin and cephalosporin in the pharmaceutical industry.

• Used to produce acid chlorides. 

• Used as a catalyst in the manufacture of acetyl cellulose and also a catalyst for condensation reactions and cyclization.

Methods of Preparation of Phosphorus Pentachloride (PCl₅)

Chemical Properties of Phosphorus Pentachloride (PCl₅)

• Phosphorus pentachloride dissociates as: PCl₅ ⇌ PCl₃ + Cl₂

• Reaction with water: PCl₅ + 4H₂O → H₃PO₄ + 5HCl

• Reaction with metal: Zn + PCl₅ → ZnCl₂ + PCl₃

• Reactions with phosphorus pentoxide: 6PCl₅ + P₄O₁₀ → 10POCl₃

• Reactions with sulfur dioxide: SO₂ + PCl₅ → POCl₃ + SOCl₂

Harmful Effects of Phosphorus Pentachloride

Phosphorus Pentachloride is a Reactive Chemical. Direct exposure to Phosphorus Pentachloride can cause weakness, nausea, headache, dizziness, and vomiting. It may damage the liver and kidneys.

As a precaution, one must be able to identify Phosphorus Pentachloride. It’s a crystalline solid whose color can range from white to pale yellow with a pungent odor. Phosphorus Pentachloride is a manufacturing agent for other chemicals, aluminum metallurgy, and the pharmaceutical industry.

Some of the acute health hazards that can be caused by Phosphorus Pentachloride are mentioned below: 

• If an individual comes in contact with Phosphorus Pentachloride, one may experience severe irritation and burning of skin and eyes with possible chronic eye damage

• Breathing in Phosphorus Pentachloride can lead to irritation in the nasal cavity and throat.

• If inhaled deeply, it can cause intense irritation and damage to the lungs resulting in coughing and/or shortness of breath. A medical emergency can also be caused because of higher exposure to Phosphorus Pentachloride. This can lead to fluid build-up in the lungs called pulmonary oedema with severe shortness of breath.

• Exposure to Phosphorus Pentachloride can cause the development of cough, phlegm in bronchitis.