At 20°C the solubility of solid naphthalene in hexane is 0.09 mol/mol of solution. Use this information and the data below to estimate the following for this system:
a) The mol fraction of naphthalene in the vapour phase in equilibrium with a saturated solution of naphthalene at 20oC.
b) The mol fraction of naphthalene in the vapor phase in equilibrium with a liquid containing 5.0 mol% naphthalene and 95 mol% hexane at 20°C.
c) The solubility of naphthalene in hexane at 40oc
Data:
Heat of melting of naphthalene: 4610 cal/mol
Heat of melting of hexane: 3119 cal/mol
Melting point of naphthalene: 80.2oC
Melting point of hexane: -95oC
Vapor pressure at 20°C:
solid naphthalene: 0.054 mmHg
liquid hexane: 122.5 mmHg
The activity coefficients of naphthalene and hexane in the liquid solution can be represented by the Regular Solution model
RT ln γA = αXB2
RT ln γB = αXA2
where α is a constant independent of temperature and composition.