Determination of boiling point of organic compounds

Dotsha J. RaheemDepartment of Chemistry College of Science University of SalahaddinDefinition of b.p.The boiling point of a liquid is the temperature at which its vapor pressure is equal to the pressure of the gas above it  In terms of intermolecular interactions the b.p. represents the energy required to overcome the various intermolecular attractions binding the molecules as a liquid (e.g. dipole-dipole attraction and hydrogen bonding) and therefore undergo a phase change into the gaseous phase . Therefore the boiling point of a liquid is also an indicator of the strength of the attractive forces between the liquid’s molecules.  The normal boiling point of a liquid is the temperature at which its vapor pressure is equal to 1 atmImportance of b.p. B.p. is a physical constant used for:1. Identification of unknown liquid compound2. Purification factors affecting b.p. Pressure  Molecular weight  Structure of the molecule & intermolecular interactions  Branching Polarity Van der Waals interactions H-bonding  Impurities Factors affecting B.P.a. When the pressure is less than 1 atm , the boiling point of the liquid is less than its normal b.p.b. P = 1 atm, the b.p. of the liquid is called normal boiling pointc. When P is greater than 1 atm, the b.p. of the liquid is greater than its normal b.p. The higher the altitude, the lower the temp at which water boils