What is Phosphorus tribromide (PBr3)?
The chemical formula of potassium tribromide is PBr3. It is a colourless liquid with sharp, penetrating order. It is used in chemical analysis, as a catalyst and in making other chemical compounds. It is used in the laboratory for the conversion of alcohols to alkyl bromides.
The structure of PBr3 is a pyramid structure. Phosphorus tribromide shows sp3 hybridization.
Table of contents
- Structure of phosphorus tribromide – PBr3
- Properties of phosphorus tribromide – PBr3
- Preparation of phosphorus tribromide – PBr3
- Chemical properties of phosphorus tribromide – PBr3
- Uses of phosphorus tribromide – PBr3
- Health hazard of phosphorus tribromide – PBr3
- Frequently Asked Questions – FAQs
Structure of phosphorus tribromide – PBr3
- P in PBr3 is sp3 hybridized in nature. Three of its sp3 orbital of P atom overlap with three bromine atoms from PBr3
- The fourth sp3 orbital of the P atom contains the lone pair of electrons.
- The bond angle between BrPBr in PBr3 is 1010.
- It is a colourless pungent smelling liquid.
Properties of phosphorus tribromide – PBr3
| Chemical formula | PBr3 |
|---|---|
| Molecular weight | 270.69 g/mol |
| Density | 2.852 g/cm3 |
| Melting point | −41.5 °C |
| Boiling point | 173.2 °C |
| Appearance | clear, colourless liquid |
Preparation of phosphorus tribromide – PBr3
- PBr3 is prepared by treating red phosphorus with bromine. An excess of phosphorus is used in order to prevent the formation of PBr5. Because the reaction is highly exothermic, it is often conducted in the presence of a diluent such as PBr3.
2 P + 3 Br2 → 2 PBr3
Chemical properties of phosphorus tribromide – PBr3
(1) It reacts with water to form phosphorous acid (H3PO3) and HBr.
PBr3 + H2O → H3PO3 + HBr
(2) Phosphorus tribromide reacts with a number of organic compounds containing the -OH group and is replaced by Br atom.
3C2H5OH + PBr3 → 3C2H5Br + H3PO3
3CH3COOH + PBr3 → 3CH3COBr + H3PO3
(3) Phosphorus tribromide reacts with Grignard reagents to form substituted phosphine.
PBr3 + 3C6H5MgBr → P(C6H5)3 + 2MgBr2
Uses of phosphorus tribromide – PBr3
- PBr3 is used as a reagent to convert alcohol to an alkyl halide.
Health hazard of phosphorus tribromide – PBr3
- Phosphorus tribromide is a corrosive chemical and contact can several irritate burn the skin and eyes with possible eye damage
- It is affected by breathing, it can irritate the nose and throat and lungs causing coughing, wheezing and shortness of breath.
Frequently Asked Questions on Phosphorus tribromide (PBr3)
What type of compound is PBr3?
PBr3 is a covalent compound. It is a colourless liquid with sharp, penetrating order. It is used in chemical analysis, as a catalyst and in making other chemical compounds.
What does the reagent PBr3 do?
PBr3 is used as a reagent to convert alcohol to an alkyl halide. It allows the conversion of chiral alcohols to bromides with retention of configuration.
3C2H5OH + PBr3 → 3C2H5Br + H3PO3
What is the name PBr3?
The name of PBr3 is phosphorus tri bromides.
Is PBr3 a base?
Phosphorus tribromide, has both properties of a Lewis base and a Lewis acid. Due to the presence of lone pair electrons over phosphorus atoms, it acts as lewis base. Due to the presence of a vacant orbital of phosphorus atoms, it acts as lewis acid.
Is Bromine a metal?
Bromine is a nonmetal. It is the only nonmetal to exist in liquid form at room temperature
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